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+# Observatoire — filtrage natif DuckDB — Plan d'implémentation
+
+> **For agentic workers:** REQUIRED SUB-SKILL: Use superpowers:subagent-driven-development (recommended) or superpowers:executing-plans to implement this plan task-by-task. Steps use checkbox (`- [ ]`) syntax for tracking.
+
+**Goal:** Remplacer le filtrage Polars sur LazyFrame dans `prepare_dashboard_data` par un requêtage natif DuckDB, pour ne matérialiser que le sous-ensemble utile au lieu de l'intégralité de la table `decp` (~1,5 M lignes).
+
+**Architecture:** Nouveau helper pur `dashboard_filters_to_sql(**filter_params) -> (where_sql, params)` dans `src/utils/table_sql.py` (modèle de `filter_query_to_sql`). `prepare_dashboard_data` devient une fonction fine qui appelle `query_marches(where_sql, params)` et retourne une `pl.DataFrame`. Les 3 appelants dans `src/pages/observatoire.py` sont adaptés à la nouvelle signature.
+
+**Tech Stack:** Python 3.12, Polars, DuckDB, Dash, pytest.
+
+**Spec:** `docs/superpowers/specs/2026-04-22-observatoire-duckdb-filters-design.md`.
+
+---
+
+## File Structure
+
+**À créer :**
+
+- `tests/test_dashboard_filters_to_sql.py` — tests unitaires du nouveau helper SQL (cas vide + cas par filtre).
+- `tests/test_prepare_dashboard_data.py` — test d'intégration léger (appel DuckDB réel sur `tests/test.parquet`).
+
+**À modifier :**
+
+- `src/utils/table_sql.py` — ajouter `dashboard_filters_to_sql` + import `datetime`/`timedelta`.
+- `src/utils/data.py` — réécrire `prepare_dashboard_data` (signature et implémentation), ajouter `query_marches` aux imports `from src.db`.
+- `src/pages/observatoire.py` — adapter 3 sites d'appel (lignes ~668, ~791, ~882) ; retirer `query_marches` de l'import `from src.db` (plus utilisé).
+- `tests/test_main.py` — supprimer `test_010_observatoire_montant_filter` (migré en test unitaire du helper).
+
+---
+
+## Task 1: Tests unitaires — cas par défaut + filtre année
+
+**Files:**
+
+- Create: `tests/test_dashboard_filters_to_sql.py`
+- Modify: `src/utils/table_sql.py`
+
+- [ ] **Step 1: Write the failing tests**
+
+Create `tests/test_dashboard_filters_to_sql.py`:
+
+```python
+from datetime import datetime, timedelta
+
+from src.utils.table_sql import dashboard_filters_to_sql
+
+
+def test_no_filters_uses_default_365_day_window():
+    where_sql, params = dashboard_filters_to_sql()
+    assert where_sql == '"dateNotification" > ?'
+    assert len(params) == 1
+    assert isinstance(params[0], datetime)
+    expected = datetime.now() - timedelta(days=365)
+    assert abs((params[0] - expected).total_seconds()) < 2
+
+
+def test_year_filter_overrides_default_window():
+    where_sql, params = dashboard_filters_to_sql(dashboard_year="2025")
+    assert where_sql == 'YEAR("dateNotification") = ?'
+    assert params == [2025]
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: FAIL with `ImportError: cannot import name 'dashboard_filters_to_sql'`.
+
+- [ ] **Step 3: Implement the helper**
+
+Add to the top of `src/utils/table_sql.py` (below existing imports):
+
+```python
+from datetime import datetime, timedelta
+```
+
+Append this function at the end of `src/utils/table_sql.py`:
+
+```python
+def dashboard_filters_to_sql(
+    dashboard_year=None,
+    dashboard_acheteur_id=None,
+    dashboard_acheteur_categorie=None,
+    dashboard_acheteur_departement_code=None,
+    dashboard_titulaire_id=None,
+    dashboard_titulaire_categorie=None,
+    dashboard_titulaire_departement_code=None,
+    dashboard_marche_type=None,
+    dashboard_marche_objet=None,
+    dashboard_marche_code_cpv=None,
+    dashboard_marche_considerations_sociales=None,
+    dashboard_marche_considerations_environnementales=None,
+    dashboard_marche_techniques=None,
+    dashboard_marche_innovant=None,
+    dashboard_marche_sous_traitance_declaree=None,
+    dashboard_montant_min=None,
+    dashboard_montant_max=None,
+) -> tuple[str, list]:
+    """Traduit les filtres du tableau de bord en (where_clause, params) DuckDB."""
+    clauses: list[str] = []
+    params: list = []
+
+    if dashboard_year:
+        clauses.append('YEAR("dateNotification") = ?')
+        params.append(int(dashboard_year))
+    else:
+        clauses.append('"dateNotification" > ?')
+        params.append(datetime.now() - timedelta(days=365))
+
+    return " AND ".join(clauses), params
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: PASS (2 tests).
+
+- [ ] **Step 5: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git add tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git commit -m "feat(observatoire): squelette de dashboard_filters_to_sql (#72)"
+```
+
+---
+
+## Task 2: Filtres d'égalité simples (catégorie, type, innovant, sous-traitance)
+
+**Files:**
+
+- Modify: `tests/test_dashboard_filters_to_sql.py`
+- Modify: `src/utils/table_sql.py`
+
+- [ ] **Step 1: Add failing tests**
+
+Append to `tests/test_dashboard_filters_to_sql.py`:
+
+```python
+def test_marche_type_equality():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_type="Marché",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "type" = ?'
+    assert params == [2025, "Marché"]
+
+
+def test_innovant_value_all_is_skipped():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_innovant="all",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ?'
+    assert params == [2025]
+
+
+def test_innovant_value_oui_adds_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_innovant="oui",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "marcheInnovant" = ?'
+    assert params == [2025, "oui"]
+
+
+def test_sous_traitance_value_non_adds_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_sous_traitance_declaree="non",
+    )
+    assert (
+        where_sql
+        == 'YEAR("dateNotification") = ? AND "sousTraitanceDeclaree" = ?'
+    )
+    assert params == [2025, "non"]
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: 4 new tests FAIL (missing clauses).
+
+- [ ] **Step 3: Extend the helper**
+
+Insert the following block in `dashboard_filters_to_sql`, **after** the `if dashboard_year / else` block and **before** `return " AND ".join(clauses), params`:
+
+```python
+    if dashboard_marche_type:
+        clauses.append('"type" = ?')
+        params.append(dashboard_marche_type)
+
+    if dashboard_marche_innovant and dashboard_marche_innovant != "all":
+        clauses.append('"marcheInnovant" = ?')
+        params.append(dashboard_marche_innovant)
+
+    if (
+        dashboard_marche_sous_traitance_declaree
+        and dashboard_marche_sous_traitance_declaree != "all"
+    ):
+        clauses.append('"sousTraitanceDeclaree" = ?')
+        params.append(dashboard_marche_sous_traitance_declaree)
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: PASS (6 tests total).
+
+- [ ] **Step 5: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git add tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git commit -m "feat(observatoire): filtres d'égalité simples dans dashboard_filters_to_sql (#72)"
+```
+
+---
+
+## Task 3: Filtres LIKE/ILIKE (ids, objet, cpv)
+
+**Files:**
+
+- Modify: `tests/test_dashboard_filters_to_sql.py`
+- Modify: `src/utils/table_sql.py`
+
+- [ ] **Step 1: Add failing tests**
+
+Append to `tests/test_dashboard_filters_to_sql.py`:
+
+```python
+def test_acheteur_id_uses_like_wildcards():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_id="12345678900010",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "acheteur_id" LIKE ?'
+    assert params == [2025, "%12345678900010%"]
+
+
+def test_titulaire_id_uses_like_wildcards():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_titulaire_id="999",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "titulaire_id" LIKE ?'
+    assert params == [2025, "%999%"]
+
+
+def test_marche_objet_uses_case_insensitive_ilike():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_objet="travaux",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "objet" ILIKE ?'
+    assert params == [2025, "%travaux%"]
+
+
+def test_code_cpv_uses_prefix_like():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_code_cpv="4521",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "codeCPV" LIKE ?'
+    assert params == [2025, "4521%"]
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: 4 new tests FAIL.
+
+- [ ] **Step 3: Extend the helper**
+
+Insert the following block, **just after** the year/default block and **before** the `if dashboard_marche_type` block:
+
+```python
+    if dashboard_acheteur_id:
+        clauses.append('"acheteur_id" LIKE ?')
+        params.append(f"%{dashboard_acheteur_id}%")
+
+    if dashboard_titulaire_id:
+        clauses.append('"titulaire_id" LIKE ?')
+        params.append(f"%{dashboard_titulaire_id}%")
+```
+
+Insert in the "marché" block, **after** `dashboard_marche_type` and **before** `dashboard_marche_innovant`:
+
+```python
+    if dashboard_marche_objet:
+        clauses.append('"objet" ILIKE ?')
+        params.append(f"%{dashboard_marche_objet}%")
+
+    if dashboard_marche_code_cpv:
+        clauses.append('"codeCPV" LIKE ?')
+        params.append(f"{dashboard_marche_code_cpv}%")
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: PASS (10 tests total).
+
+- [ ] **Step 5: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git add tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git commit -m "feat(observatoire): filtres LIKE/ILIKE dans dashboard_filters_to_sql (#72)"
+```
+
+---
+
+## Task 4: Filtre IN (départements) + skip conditionnel par ID
+
+**Files:**
+
+- Modify: `tests/test_dashboard_filters_to_sql.py`
+- Modify: `src/utils/table_sql.py`
+
+- [ ] **Step 1: Add failing tests**
+
+Append to `tests/test_dashboard_filters_to_sql.py`:
+
+```python
+def test_acheteur_departement_multiple_uses_in_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_departement_code=["75", "92", "93"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        'AND "acheteur_departement_code" IN (?, ?, ?)'
+    )
+    assert params == [2025, "75", "92", "93"]
+
+
+def test_acheteur_categorie_adds_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_categorie="Commune",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "acheteur_categorie" = ?'
+    assert params == [2025, "Commune"]
+
+
+def test_titulaire_categorie_and_departement():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_titulaire_categorie="PME",
+        dashboard_titulaire_departement_code=["35"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        'AND "titulaire_categorie" = ? '
+        'AND "titulaire_departement_code" IN (?)'
+    )
+    assert params == [2025, "PME", "35"]
+
+
+def test_acheteur_id_present_skips_categorie_and_departement():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_id="123",
+        dashboard_acheteur_categorie="Commune",
+        dashboard_acheteur_departement_code=["75"],
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "acheteur_id" LIKE ?'
+    assert params == [2025, "%123%"]
+
+
+def test_titulaire_id_present_skips_categorie_and_departement():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_titulaire_id="999",
+        dashboard_titulaire_categorie="PME",
+        dashboard_titulaire_departement_code=["35"],
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "titulaire_id" LIKE ?'
+    assert params == [2025, "%999%"]
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: 5 new tests FAIL.
+
+- [ ] **Step 3: Refactor the helper with conditional skip**
+
+Replace the two simple `if dashboard_acheteur_id` / `if dashboard_titulaire_id` blocks added in Task 3 with the nested form:
+
+```python
+    if dashboard_acheteur_id:
+        clauses.append('"acheteur_id" LIKE ?')
+        params.append(f"%{dashboard_acheteur_id}%")
+    else:
+        if dashboard_acheteur_categorie:
+            clauses.append('"acheteur_categorie" = ?')
+            params.append(dashboard_acheteur_categorie)
+        if dashboard_acheteur_departement_code:
+            placeholders = ", ".join(["?"] * len(dashboard_acheteur_departement_code))
+            clauses.append(f'"acheteur_departement_code" IN ({placeholders})')
+            params.extend(dashboard_acheteur_departement_code)
+
+    if dashboard_titulaire_id:
+        clauses.append('"titulaire_id" LIKE ?')
+        params.append(f"%{dashboard_titulaire_id}%")
+    else:
+        if dashboard_titulaire_categorie:
+            clauses.append('"titulaire_categorie" = ?')
+            params.append(dashboard_titulaire_categorie)
+        if dashboard_titulaire_departement_code:
+            placeholders = ", ".join(
+                ["?"] * len(dashboard_titulaire_departement_code)
+            )
+            clauses.append(f'"titulaire_departement_code" IN ({placeholders})')
+            params.extend(dashboard_titulaire_departement_code)
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: PASS (15 tests total).
+
+- [ ] **Step 5: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git add tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git commit -m "feat(observatoire): IN départements et skip conditionnel par ID (#72)"
+```
+
+---
+
+## Task 5: Filtre liste (techniques, considérations sociales/environnementales)
+
+**Files:**
+
+- Modify: `tests/test_dashboard_filters_to_sql.py`
+- Modify: `src/utils/table_sql.py`
+
+- [ ] **Step 1: Add failing tests**
+
+Append to `tests/test_dashboard_filters_to_sql.py`:
+
+```python
+def test_marche_techniques_uses_list_has_any():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_techniques=["Enchère", "Accord-cadre"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        "AND list_has_any(string_split(\"techniques\", ', '), ?::VARCHAR[])"
+    )
+    assert params == [2025, ["Enchère", "Accord-cadre"]]
+
+
+def test_considerations_sociales_uses_list_has_any():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_considerations_sociales=["Clause sociale"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        "AND list_has_any(string_split(\"considerationsSociales\", ', '), ?::VARCHAR[])"
+    )
+    assert params == [2025, ["Clause sociale"]]
+
+
+def test_considerations_environnementales_uses_list_has_any():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_considerations_environnementales=["Clause env."],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        "AND list_has_any(string_split(\"considerationsEnvironnementales\", ', '), ?::VARCHAR[])"
+    )
+    assert params == [2025, ["Clause env."]]
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: 3 new tests FAIL.
+
+- [ ] **Step 3: Extend the helper**
+
+Insert the following block in `dashboard_filters_to_sql`, **after** the `dashboard_marche_sous_traitance_declaree` block and **before** `return " AND ".join(clauses), params`:
+
+```python
+    if dashboard_marche_techniques:
+        clauses.append(
+            "list_has_any(string_split(\"techniques\", ', '), ?::VARCHAR[])"
+        )
+        params.append(list(dashboard_marche_techniques))
+
+    if dashboard_marche_considerations_sociales:
+        clauses.append(
+            "list_has_any(string_split(\"considerationsSociales\", ', '), ?::VARCHAR[])"
+        )
+        params.append(list(dashboard_marche_considerations_sociales))
+
+    if dashboard_marche_considerations_environnementales:
+        clauses.append(
+            "list_has_any(string_split(\"considerationsEnvironnementales\", ', '), ?::VARCHAR[])"
+        )
+        params.append(list(dashboard_marche_considerations_environnementales))
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: PASS (18 tests total).
+
+- [ ] **Step 5: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git add tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git commit -m "feat(observatoire): filtres liste via list_has_any (#72)"
+```
+
+---
+
+## Task 6: Filtres montant min/max (incluant 0)
+
+**Files:**
+
+- Modify: `tests/test_dashboard_filters_to_sql.py`
+- Modify: `src/utils/table_sql.py`
+
+- [ ] **Step 1: Add failing tests**
+
+Append to `tests/test_dashboard_filters_to_sql.py`:
+
+```python
+def test_montant_min_only():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_min=1000,
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "montant" >= ?'
+    assert params == [2025, 1000]
+
+
+def test_montant_max_only():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_max=500,
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "montant" <= ?'
+    assert params == [2025, 500]
+
+
+def test_montant_zero_is_a_valid_lower_bound():
+    # 0 est falsy mais reste un filtre valide (distinct de None)
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_min=0,
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "montant" >= ?'
+    assert params == [2025, 0]
+
+
+def test_montant_min_and_max_combined():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_min=100,
+        dashboard_montant_max=1000,
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? AND "montant" >= ? AND "montant" <= ?'
+    )
+    assert params == [2025, 100, 1000]
+```
+
+- [ ] **Step 2: Run tests to verify they fail**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: 4 new tests FAIL.
+
+- [ ] **Step 3: Extend the helper**
+
+Insert at the very end of `dashboard_filters_to_sql`, **just before** `return " AND ".join(clauses), params`:
+
+```python
+    if dashboard_montant_min is not None:
+        clauses.append('"montant" >= ?')
+        params.append(dashboard_montant_min)
+
+    if dashboard_montant_max is not None:
+        clauses.append('"montant" <= ?')
+        params.append(dashboard_montant_max)
+```
+
+- [ ] **Step 4: Run tests to verify they pass**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+Expected: PASS (22 tests total).
+
+- [ ] **Step 5: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git add tests/test_dashboard_filters_to_sql.py src/utils/table_sql.py
+rtk git commit -m "feat(observatoire): filtres montant min/max (#72)"
+```
+
+---
+
+## Task 7: Réécriture de `prepare_dashboard_data`
+
+**Files:**
+
+- Modify: `src/utils/data.py`
+- Modify: `tests/test_main.py` (supprimer `test_010_observatoire_montant_filter`)
+
+- [ ] **Step 1: Remove the obsolete Polars-based test**
+
+Delete the function `test_010_observatoire_montant_filter` from `tests/test_main.py` (lines ~218-256). La couverture du filtre montant est déjà assurée par les tests unitaires `test_montant_*` de la Task 6.
+
+- [ ] **Step 2: Rewrite `prepare_dashboard_data`**
+
+Replace the entire `prepare_dashboard_data` function in `src/utils/data.py` (lines ~86-194) with:
+
+```python
+def prepare_dashboard_data(**filter_params) -> pl.DataFrame:
+    """Exécute la requête DuckDB filtrée pour le tableau de bord.
+
+    Retourne une pl.DataFrame matérialisée uniquement pour le sous-ensemble
+    correspondant aux filtres. Les appelants qui ont besoin d'une LazyFrame
+    appellent `.lazy()` sur le résultat.
+    """
+    from src.utils.table_sql import dashboard_filters_to_sql
+
+    where_sql, params = dashboard_filters_to_sql(**filter_params)
+    return query_marches(where_sql=where_sql, params=params)
+```
+
+Update the import at the top of `src/utils/data.py`:
+
+```python
+from src.db import get_cursor, query_marches, schema
+```
+
+Remove the now-unused import in `src/utils/data.py`:
+
+```python
+from datetime import datetime, timedelta
+```
+
+(Si `datetime` n'est plus référencé dans `data.py` hors de `prepare_dashboard_data`, sinon garder.)
+
+**Vérification rapide à effectuer avant de supprimer `datetime`/`timedelta`** :
+
+```bash
+rtk grep -n "datetime\|timedelta" src/utils/data.py
+```
+
+Si d'autres occurrences existent, conserver les imports.
+
+- [ ] **Step 3: Run the full test suite**
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py tests/test_main.py -v -k "not selenium and not dash_duo"`
+
+Ou, si filter n'est pas pratique :
+
+Run: `rtk pytest tests/test_dashboard_filters_to_sql.py -v`
+
+Expected: PASS (22 tests).
+
+- [ ] **Step 4: Commit**
+
+```bash
+rtk pre-commit run --files src/utils/data.py tests/test_main.py
+rtk git add src/utils/data.py tests/test_main.py
+rtk git commit -m "refactor(observatoire): prepare_dashboard_data utilise DuckDB (#72)"
+```
+
+---
+
+## Task 8: Adaptation des 3 appelants dans `observatoire.py`
+
+**Files:**
+
+- Modify: `src/pages/observatoire.py`
+
+- [ ] **Step 1: Update `_compute_dashboard_children`**
+
+Remplacer dans `src/pages/observatoire.py` (autour des lignes 660-670) :
+
+```python
+@cache.memoize()
+def _compute_dashboard_children(filter_params_normalized: tuple):
+    logger.debug("Cache miss — computing dashboard")
+    filter_params = {
+        k: (list(v) if isinstance(v, tuple) else v) for k, v in filter_params_normalized
+    }
+
+    lff: pl.LazyFrame = query_marches().lazy()
+    lff = prepare_dashboard_data(lff=lff, **filter_params)
+
+    dff = lff.collect(engine="streaming")
+```
+
+Par :
+
+```python
+@cache.memoize()
+def _compute_dashboard_children(filter_params_normalized: tuple):
+    logger.debug("Cache miss — computing dashboard")
+    filter_params = {
+        k: (list(v) if isinstance(v, tuple) else v) for k, v in filter_params_normalized
+    }
+
+    dff = prepare_dashboard_data(**filter_params)
+    lff = dff.lazy()
+```
+
+Le reste de la fonction (à partir de `df_per_uid = ...`) est inchangé.
+
+- [ ] **Step 2: Update `download_observatoire`**
+
+Remplacer dans `src/pages/observatoire.py` (autour des lignes 789-800) :
+
+```python
+def download_observatoire(_n_clicks, filter_params, hidden_columns):
+    lff = prepare_dashboard_data(lff=query_marches().lazy(), **(filter_params or {}))
+
+    if hidden_columns:
+        lff = lff.drop(hidden_columns)
+
+    def to_bytes(buffer):
+        lff.collect(engine="streaming").write_excel(buffer, worksheet="DECP")
+
+    date = datetime.now().strftime("%Y-%m-%d_%H:%M:%S")
+    return dcc.send_bytes(to_bytes, filename=f"decp_observatoire_{date}.xlsx")
+```
+
+Par :
+
+```python
+def download_observatoire(_n_clicks, filter_params, hidden_columns):
+    dff = prepare_dashboard_data(**(filter_params or {}))
+
+    if hidden_columns:
+        dff = dff.drop(hidden_columns)
+
+    def to_bytes(buffer):
+        dff.write_excel(buffer, worksheet="DECP")
+
+    date = datetime.now().strftime("%Y-%m-%d_%H:%M:%S")
+    return dcc.send_bytes(to_bytes, filename=f"decp_observatoire_{date}.xlsx")
+```
+
+- [ ] **Step 3: Update `populate_preview_table`**
+
+Remplacer dans `src/pages/observatoire.py` (autour des lignes 879-892) :
+
+```python
+    if not is_open:
+        return (no_update,) * 9
+
+    lff = prepare_dashboard_data(lff=query_marches().lazy(), **(filter_params or {}))
+
+    return prepare_table_data(
+        lff,
+        data_timestamp,
+        filter_query,
+        page_current,
+        page_size,
+        sort_by,
+        "observatoire-preview",
+    )
+```
+
+Par :
+
+```python
+    if not is_open:
+        return (no_update,) * 9
+
+    dff = prepare_dashboard_data(**(filter_params or {}))
+
+    return prepare_table_data(
+        dff.lazy(),
+        data_timestamp,
+        filter_query,
+        page_current,
+        page_size,
+        sort_by,
+        "observatoire-preview",
+    )
+```
+
+- [ ] **Step 4: Remove unused `query_marches` import**
+
+Dans `src/pages/observatoire.py`, ligne ~19 :
+
+```python
+from src.db import query_marches, schema
+```
+
+Devient :
+
+```python
+from src.db import schema
+```
+
+Vérifier avant de committer :
+
+```bash
+rtk grep -n "query_marches" src/pages/observatoire.py
+```
+
+Expected: aucun résultat (ou uniquement des commentaires).
+
+- [ ] **Step 5: Smoke test**
+
+Démarrer l'app et naviguer sur `/observatoire`, vérifier à la main que :
+
+- Les cartes s'affichent.
+- Un filtre année se propage.
+- Un filtre acheteur par SIRET partiel fonctionne.
+- Un filtre département (multi-valeur) fonctionne.
+- Un filtre montant_min fonctionne.
+- Le bouton « Télécharger au format Excel » génère un fichier non vide.
+- Le bouton « Voir les données » ouvre l'offcanvas et peuple la table.
+
+Run: `python run.py`
+
+Expected: app démarre sans erreur ; les filtres se comportent comme avant.
+
+- [ ] **Step 6: Commit**
+
+```bash
+rtk pre-commit run --files src/pages/observatoire.py
+rtk git add src/pages/observatoire.py
+rtk git commit -m "refactor(observatoire): appelants utilisent la nouvelle signature (#72)"
+```
+
+---
+
+## Task 9: Test d'intégration — `prepare_dashboard_data` sur `tests/test.parquet`
+
+**Files:**
+
+- Create: `tests/test_prepare_dashboard_data.py`
+
+- [ ] **Step 1: Write the failing test**
+
+Le but : vérifier que la fonction s'exécute réellement contre DuckDB, retourne une `pl.DataFrame`, et applique bien les filtres simples. `conftest.py` construit `tests/test.parquet` avec un jeu de données d'une ligne : acheteur_id `123`, acheteur_departement_code `75`, dateNotification `2025-01-01`, montant `10`.
+
+Create `tests/test_prepare_dashboard_data.py`:
+
+```python
+import polars as pl
+
+
+def test_returns_dataframe_with_year_filter():
+    from src.utils.data import prepare_dashboard_data
+
+    dff = prepare_dashboard_data(dashboard_year="2025")
+    assert isinstance(dff, pl.DataFrame)
+    assert dff.height == 1
+
+
+def test_year_mismatch_returns_empty():
+    from src.utils.data import prepare_dashboard_data
+
+    dff = prepare_dashboard_data(dashboard_year="2024")
+    assert isinstance(dff, pl.DataFrame)
+    assert dff.height == 0
+
+
+def test_acheteur_id_partial_match():
+    from src.utils.data import prepare_dashboard_data
+
+    dff = prepare_dashboard_data(
+        dashboard_year="2025",
+        dashboard_acheteur_id="12",
+    )
+    assert dff.height == 1
+
+
+def test_departement_in_clause():
+    from src.utils.data import prepare_dashboard_data
+
+    dff = prepare_dashboard_data(
+        dashboard_year="2025",
+        dashboard_acheteur_departement_code=["75", "92"],
+    )
+    assert dff.height == 1
+
+
+def test_montant_min_above_value_excludes_row():
+    from src.utils.data import prepare_dashboard_data
+
+    dff = prepare_dashboard_data(
+        dashboard_year="2025",
+        dashboard_montant_min=1000,
+    )
+    assert dff.height == 0
+```
+
+- [ ] **Step 2: Run the test**
+
+Run: `rtk pytest tests/test_prepare_dashboard_data.py -v`
+Expected: PASS (5 tests).
+
+- [ ] **Step 3: Commit**
+
+```bash
+rtk pre-commit run --files tests/test_prepare_dashboard_data.py
+rtk git add tests/test_prepare_dashboard_data.py
+rtk git commit -m "test(observatoire): intégration DuckDB pour prepare_dashboard_data (#72)"
+```
+
+---
+
+## Task 10: Vérification finale
+
+**Files:** (aucune modification)
+
+- [ ] **Step 1: Run the full test suite**
+
+Run: `rtk pytest -v`
+Expected: tous les tests unitaires passent. Les tests Selenium peuvent échouer si Chrome n'est pas disponible — ce n'est pas bloquant s'ils étaient déjà rouges avant.
+
+- [ ] **Step 2: Check for leftover references**
+
+Run: `rtk grep -rn "prepare_dashboard_data(lff" src/ tests/`
+Expected: aucun résultat (plus d'appels avec l'ancienne signature).
+
+Run: `rtk grep -rn "query_marches().lazy()" src/`
+Expected: aucun résultat (ou uniquement dans `src/utils/table.py:prepare_table_data` pour le fallback).
+
+- [ ] **Step 3: Confirm `datetime`/`timedelta` in data.py if needed**
+
+Run: `rtk grep -n "datetime\|timedelta" src/utils/data.py`
+
+Si aucune occurrence hors imports, vérifier que les imports inutiles ont bien été retirés dans Task 7.
+
+- [ ] **Step 4: Manual timing sanity check (optionnel)**
+
+Si possible, comparer informellement le temps de `_compute_dashboard_children` sur un filtre sélectif (ex. un département) avant/après. Pas de benchmark formel attendu.
+
+- [ ] **Step 5: Push (manuel, à l'initiative de l'utilisateur)**
+
+Conformément aux consignes projet, ne jamais `git push`. Laisser l'utilisateur pousser la branche `feature/72_observatoire_duckdb_filters` et ouvrir la PR.
diff --git a/docs/superpowers/specs/2026-04-22-observatoire-duckdb-filters-design.md b/docs/superpowers/specs/2026-04-22-observatoire-duckdb-filters-design.md
new file mode 100644
index 0000000..6d8ebaf
--- /dev/null
+++ b/docs/superpowers/specs/2026-04-22-observatoire-duckdb-filters-design.md
@@ -0,0 +1,206 @@
+# Observatoire — filtrage natif DuckDB
+
+## Contexte
+
+La page `/observatoire` construit ses cartes, ses téléchargements et sa prévisualisation
+tabulaire à partir de la fonction `prepare_dashboard_data` (dans `src/utils/data.py`).
+Aujourd'hui, cette fonction prend une `pl.LazyFrame` — typiquement obtenue par
+`query_marches().lazy()` — et applique une série de filtres côté Polars.
+
+`query_marches()` matérialise l'intégralité de la table `decp` (~1,5 M lignes) en
+DataFrame Polars, même lorsqu'un utilisateur applique des filtres restrictifs. Les
+filtres sont ensuite appliqués sur cet ensemble déjà matérialisé.
+
+Le pattern utilisé par `_fetch_page_sql` (dans `src/utils/table.py`) montre comment
+déléguer le filtrage à DuckDB :
+
+1. Un traducteur (`filter_query_to_sql`, dans `src/utils/table_sql.py`) transforme le
+   DSL utilisateur en `(where_sql, params)`.
+2. `query_marches(where_sql=..., params=...)` ne matérialise que le sous-ensemble utile.
+
+Ce spec décrit comment appliquer ce même pattern aux filtres de l'observatoire.
+
+## Objectifs
+
+- Réduire la consommation mémoire et le temps de chaque callback de l'observatoire
+  en poussant le filtrage au niveau DuckDB.
+- Conserver strictement la sémantique des filtres actuels (pas de régression
+  fonctionnelle).
+- Garder une frontière claire : un helper pur `dashboard_filters_to_sql` qui ne
+  touche pas à la base, et une `prepare_dashboard_data` fine qui appelle DuckDB.
+
+## Non-objectifs
+
+- Pas de refonte de l'UI de filtres.
+- Pas d'optimisation ou de cache supplémentaire autour de
+  `_compute_dashboard_children` (déjà `@cache.memoize()`).
+- Pas de changement du comportement par défaut (365 derniers jours quand aucune
+  année n'est sélectionnée).
+
+## Architecture
+
+### Nouveau helper — `src/utils/table_sql.py`
+
+```python
+def dashboard_filters_to_sql(
+    dashboard_year=None,
+    dashboard_acheteur_id=None,
+    dashboard_acheteur_categorie=None,
+    dashboard_acheteur_departement_code=None,
+    dashboard_titulaire_id=None,
+    dashboard_titulaire_categorie=None,
+    dashboard_titulaire_departement_code=None,
+    dashboard_marche_type=None,
+    dashboard_marche_objet=None,
+    dashboard_marche_code_cpv=None,
+    dashboard_marche_considerations_sociales=None,
+    dashboard_marche_considerations_environnementales=None,
+    dashboard_marche_techniques=None,
+    dashboard_marche_innovant=None,
+    dashboard_marche_sous_traitance_declaree=None,
+    dashboard_montant_min=None,
+    dashboard_montant_max=None,
+) -> tuple[str, list]:
+    """Traduit les filtres du tableau de bord en (where_clause, params) DuckDB."""
+```
+
+Fonction pure, sans accès à la base. Même signature que `prepare_dashboard_data`
+actuelle (hors `lff`). Retourne `("TRUE", [])` si aucun filtre n'est actif.
+
+### Réécriture — `prepare_dashboard_data` (`src/utils/data.py`)
+
+```python
+def prepare_dashboard_data(**filter_params) -> pl.DataFrame:
+    where_sql, params = dashboard_filters_to_sql(**filter_params)
+    return query_marches(where_sql=where_sql, params=params)
+```
+
+- **Signature** : suppression du paramètre `lff`. Retour `pl.DataFrame` (et non plus
+  `pl.LazyFrame`).
+- Les appelants qui ont besoin d'une LazyFrame appellent `.lazy()` sur le résultat.
+
+### Appelants — `src/pages/observatoire.py`
+
+Trois sites d'appel à adapter :
+
+1. **`_compute_dashboard_children`** (ligne ~668) — on remplace
+
+   ```python
+   lff: pl.LazyFrame = query_marches().lazy()
+   lff = prepare_dashboard_data(lff=lff, **filter_params)
+   dff = lff.collect(engine="streaming")
+   ```
+
+   par
+
+   ```python
+   dff = prepare_dashboard_data(**filter_params)
+   lff = dff.lazy()
+   ```
+
+   Les appels existants à `make_donut`, `get_distance_histogram`, `get_top_org_table`,
+   `get_barchart_sources` continuent de recevoir `lff` ; `get_geographic_maps`
+   continue de recevoir `dff`. `df_per_uid` est calculé à partir de `dff`.
+
+2. **`download_observatoire`** (ligne ~791) —
+
+   ```python
+   dff = prepare_dashboard_data(**(filter_params or {}))
+   if hidden_columns:
+       dff = dff.drop(hidden_columns)
+   def to_bytes(buffer):
+       dff.write_excel(buffer, worksheet="DECP")
+   ```
+
+3. **`populate_preview_table`** (ligne ~882) —
+   ```python
+   dff = prepare_dashboard_data(**(filter_params or {}))
+   return prepare_table_data(
+       dff.lazy(),  # prepare_table_data accepte une LazyFrame
+       ...
+   )
+   ```
+
+## Traduction des filtres
+
+| Filtre                                                    | Actuel (Polars)                                            | Cible (SQL DuckDB)                                             |
+| --------------------------------------------------------- | ---------------------------------------------------------- | -------------------------------------------------------------- |
+| `dashboard_year` (présent)                                | `dt.year() == int(year)`                                   | `YEAR("dateNotification") = ?`                                 |
+| `dashboard_year` (absent) — comportement par défaut       | `> now - 365j`                                             | `"dateNotification" > ?` (datetime calculé à l'appel)          |
+| `dashboard_acheteur_id`                                   | `str.contains(val)`                                        | `"acheteur_id" LIKE ?` avec `%val%`                            |
+| `dashboard_acheteur_categorie`                            | `== val` (skip si acheteur_id présent)                     | `"acheteur_categorie" = ?`                                     |
+| `dashboard_acheteur_departement_code`                     | `is_in(list)` (skip si acheteur_id présent)                | `"acheteur_departement_code" IN (?, ?, ...)`                   |
+| `dashboard_titulaire_id`                                  | idem acheteur                                              | idem                                                           |
+| `dashboard_titulaire_categorie`                           | idem                                                       | idem                                                           |
+| `dashboard_titulaire_departement_code`                    | idem                                                       | idem                                                           |
+| `dashboard_marche_type`                                   | `== val`                                                   | `"type" = ?`                                                   |
+| `dashboard_marche_objet`                                  | `str.contains("(?i)val")`                                  | `"objet" ILIKE ?` avec `%val%`                                 |
+| `dashboard_marche_code_cpv`                               | `str.starts_with(val)`                                     | `"codeCPV" LIKE ?` avec `val%`                                 |
+| `dashboard_marche_techniques`                             | `str.split(", ").list.set_intersection(xs).list.len() > 0` | `list_has_any(string_split("techniques", ', '), ?::VARCHAR[])` |
+| `dashboard_marche_considerations_sociales`                | idem                                                       | idem sur `"considerationsSociales"`                            |
+| `dashboard_marche_considerations_environnementales`       | idem                                                       | idem sur `"considerationsEnvironnementales"`                   |
+| `dashboard_marche_innovant` (`"oui"`/`"non"`, sinon skip) | `== val`                                                   | `"marcheInnovant" = ?`                                         |
+| `dashboard_marche_sous_traitance_declaree`                | idem                                                       | `"sousTraitanceDeclaree" = ?`                                  |
+| `dashboard_montant_min`                                   | `>= val`                                                   | `"montant" >= ?`                                               |
+| `dashboard_montant_max`                                   | `<= val`                                                   | `"montant" <= ?`                                               |
+
+**Logique conditionnelle conservée** : si `dashboard_acheteur_id` est fourni, les filtres
+`categorie` et `departement_code` acheteur sont ignorés (même chose pour titulaire).
+
+**Traitement des valeurs spéciales** :
+
+- `dashboard_marche_innovant` / `dashboard_marche_sous_traitance_declaree` : valeur
+  `"all"` ou falsy → aucun filtre ajouté.
+- `dashboard_year` : converti en `int` avant injection.
+- `dashboard_montant_min` / `_max` : `None` → aucun filtre (distinct de `0`, qui reste
+  un filtre valide via `>=` ou `<=`).
+
+**Sécurité SQL** : toutes les valeurs utilisateurs passent par DuckDB en paramètres liés
+(`?`). Seuls des noms de colonnes statiques (contrôlés par le code) sont injectés dans le
+fragment SQL via `f"..."`. Pas de différence avec le pattern existant de
+`filter_query_to_sql`.
+
+## Tests
+
+### Unitaires (nouveaux)
+
+Nouveau fichier `tests/test_dashboard_filters_to_sql.py` :
+
+- Cas vide → `("TRUE", [])`.
+- Un seul filtre simple (année, type, etc.) → fragment SQL et params attendus.
+- Filtre montant min/max (migration de l'actuel `test_010_observatoire_montant_filter`).
+- Filtre liste (techniques, considerationsSociales) → usage de `list_has_any`.
+- Filtre acheteur_id fourni → catégorie/département acheteur ignorés.
+- Filtre `"all"` / `None` sur innovant/sous_traitance → aucun fragment ajouté.
+- Comportement par défaut sans année → fragment `"dateNotification" > ?` avec un param
+  datetime à ~365 j dans le passé (tolérance de quelques secondes).
+
+### Intégration (nouveau, léger)
+
+Un test qui appelle `prepare_dashboard_data` contre `tests/test.parquet` avec un ou
+deux filtres connus, vérifie le `height` et la bonne nature du retour (`pl.DataFrame`).
+
+### Test Selenium existant
+
+`test_009_observatoire_filter_persistence` et `test_008_observatoire_navigation_from_search`
+ne touchent pas à la signature ; ils doivent continuer à passer.
+
+## Risques et migration
+
+- **Risque sémantique** : la fonction Polars `str.contains` utilisée pour les IDs est
+  un regex. Les utilisateurs attendent probablement un contains littéral sur un SIRET
+  (14 chiffres). Le passage à `LIKE '%val%'` est neutre si la valeur ne contient pas de
+  caractère spécial regex — ce qui est le cas pour des SIRET. **Hypothèse** acceptée :
+  le contenu `dashboard_acheteur_id`/`dashboard_titulaire_id` est alphanumérique.
+- **Risque de drift du cache** : la date "365 derniers jours" n'est pas incluse dans
+  la clé de cache de `_compute_dashboard_children`. C'est un comportement pré-existant
+  ; non traité par ce spec.
+- **Import circulaire** : `src/utils/data.py` importe déjà depuis `src/db.py`.
+  `src/utils/table_sql.py` importe depuis `src/utils/table.py`. Pas de nouveau cycle.
+
+## Succès
+
+- Les 3 callbacks de l'observatoire restent fonctionnellement équivalents.
+- Les tests unitaires et d'intégration passent.
+- Une inspection manuelle confirme un temps d'exécution réduit sur un filtre
+  sélectif (par ex. un département + une année).
diff --git a/src/pages/observatoire.py b/src/pages/observatoire.py
index 2391a2a..e58c9ba 100644
--- a/src/pages/observatoire.py
+++ b/src/pages/observatoire.py
@@ -16,7 +16,7 @@ from dash import (
     register_page,
 )
 
-from src.db import query_marches, schema
+from src.db import schema
 from src.figures import (
     DataTable,
     get_barchart_sources,
@@ -508,17 +508,26 @@ Alors, on fait comment ?
                 size="xl",
             ),
             # DataTable
-            html.Div(
-                className="marches_table",
-                children=DataTable(
-                    dtid="observatoire-preview-table",
-                    page_size=5,
-                    page_action="custom",
-                    sort_action="custom",
-                    filter_action="custom",
-                    hidden_columns=[],
-                    columns=[{"id": col, "name": col} for col in OBSERVATOIRE_COLUMNS],
-                ),
+            dcc.Loading(
+                overlay_style={"visibility": "visible", "filter": "blur(2px)"},
+                id="loading-statistques",
+                type="default",
+                children=[
+                    html.Div(
+                        className="marches_table",
+                        children=DataTable(
+                            dtid="observatoire-preview-table",
+                            page_size=5,
+                            page_action="custom",
+                            sort_action="custom",
+                            filter_action="custom",
+                            hidden_columns=[],
+                            columns=[
+                                {"id": col, "name": col} for col in OBSERVATOIRE_COLUMNS
+                            ],
+                        ),
+                    )
+                ],
             ),
         ],
     ),
@@ -664,10 +673,8 @@ def _compute_dashboard_children(filter_params_normalized: tuple):
         k: (list(v) if isinstance(v, tuple) else v) for k, v in filter_params_normalized
     }
 
-    lff: pl.LazyFrame = query_marches().lazy()
-    lff = prepare_dashboard_data(lff=lff, **filter_params)
-
-    dff = lff.collect(engine="streaming")
+    dff = prepare_dashboard_data(**filter_params)
+    lff = dff.lazy()
 
     df_per_uid = (
         dff.select("uid", "montant").group_by("uid").agg(pl.col("montant").first())
@@ -788,13 +795,13 @@ def update_dashboard_cards(*filter_values):
     prevent_initial_call=True,
 )
 def download_observatoire(_n_clicks, filter_params, hidden_columns):
-    lff = prepare_dashboard_data(lff=query_marches().lazy(), **(filter_params or {}))
+    dff = prepare_dashboard_data(**(filter_params or {}))
 
     if hidden_columns:
-        lff = lff.drop(hidden_columns)
+        dff = dff.drop(hidden_columns)
 
     def to_bytes(buffer):
-        lff.collect(engine="streaming").write_excel(buffer, worksheet="DECP")
+        dff.write_excel(buffer, worksheet="DECP")
 
     date = datetime.now().strftime("%Y-%m-%d_%H:%M:%S")
     return dcc.send_bytes(to_bytes, filename=f"decp_observatoire_{date}.xlsx")
@@ -879,10 +886,10 @@ def populate_preview_table(
     if not is_open:
         return (no_update,) * 9
 
-    lff = prepare_dashboard_data(lff=query_marches().lazy(), **(filter_params or {}))
+    dff = prepare_dashboard_data(**(filter_params or {}))
 
     return prepare_table_data(
-        lff,
+        dff.lazy(),
         data_timestamp,
         filter_query,
         page_current,
diff --git a/src/utils/data.py b/src/utils/data.py
index e4817be..cd54f40 100644
--- a/src/utils/data.py
+++ b/src/utils/data.py
@@ -2,12 +2,11 @@ import json
 import logging
 import os
 from collections import OrderedDict
-from datetime import datetime, timedelta
 
 import polars as pl
 from httpx import HTTPError, get
 
-from src.db import get_cursor, schema
+from src.db import get_cursor, query_marches, schema
 from src.utils import logger
 
 logging.getLogger("httpx").setLevel("WARNING")
@@ -83,115 +82,17 @@ def get_data_schema() -> dict:
     return new_schema
 
 
-def prepare_dashboard_data(
-    lff: pl.LazyFrame,
-    dashboard_year=None,
-    dashboard_acheteur_id=None,
-    dashboard_acheteur_categorie=None,
-    dashboard_acheteur_departement_code=None,
-    dashboard_titulaire_id=None,
-    dashboard_titulaire_categorie=None,
-    dashboard_titulaire_departement_code=None,
-    dashboard_marche_type=None,
-    dashboard_marche_objet=None,
-    dashboard_marche_code_cpv=None,
-    dashboard_marche_considerations_sociales=None,
-    dashboard_marche_considerations_environnementales=None,
-    dashboard_marche_techniques=None,
-    dashboard_marche_innovant=None,
-    dashboard_marche_sous_traitance_declaree=None,
-    dashboard_montant_min=None,
-    dashboard_montant_max=None,
-) -> pl.LazyFrame:
-    if dashboard_year:
-        lff = lff.filter(pl.col("dateNotification").dt.year() == int(dashboard_year))
-    else:
-        lff = lff.filter(
-            pl.col("dateNotification") > (datetime.now() - timedelta(days=365))
-        )
+def prepare_dashboard_data(**filter_params) -> pl.DataFrame:
+    """Exécute la requête DuckDB filtrée pour le tableau de bord.
 
-    if dashboard_acheteur_id:
-        lff = lff.filter(pl.col("acheteur_id").str.contains(dashboard_acheteur_id))
-    else:
-        if dashboard_acheteur_categorie:
-            lff = lff.filter(
-                pl.col("acheteur_categorie") == dashboard_acheteur_categorie
-            )
-        if dashboard_acheteur_departement_code:
-            lff = lff.filter(
-                pl.col("acheteur_departement_code").is_in(
-                    dashboard_acheteur_departement_code
-                )
-            )
+    Retourne une pl.DataFrame matérialisée uniquement pour le sous-ensemble
+    correspondant aux filtres. Les appelants qui ont besoin d'une LazyFrame
+    appellent `.lazy()` sur le résultat.
+    """
+    from src.utils.table_sql import dashboard_filters_to_sql
 
-    if dashboard_titulaire_id:
-        lff = lff.filter(pl.col("titulaire_id").str.contains(dashboard_titulaire_id))
-    else:
-        if dashboard_titulaire_categorie:
-            lff = lff.filter(
-                pl.col("titulaire_categorie") == dashboard_titulaire_categorie
-            )
-        if dashboard_titulaire_departement_code:
-            lff = lff.filter(
-                pl.col("titulaire_departement_code").is_in(
-                    dashboard_titulaire_departement_code
-                )
-            )
-
-    if dashboard_marche_type:
-        lff = lff.filter(pl.col("type") == dashboard_marche_type)
-
-    if dashboard_marche_objet:
-        lff = lff.filter(pl.col("objet").str.contains(f"(?i){dashboard_marche_objet}"))
-
-    if dashboard_marche_code_cpv:
-        lff = lff.filter(pl.col("codeCPV").str.starts_with(dashboard_marche_code_cpv))
-
-    if dashboard_marche_innovant and dashboard_marche_innovant != "all":
-        lff = lff.filter(pl.col("marcheInnovant") == dashboard_marche_innovant)
-
-    if (
-        dashboard_marche_sous_traitance_declaree
-        and dashboard_marche_sous_traitance_declaree != "all"
-    ):
-        lff = lff.filter(
-            pl.col("sousTraitanceDeclaree") == dashboard_marche_sous_traitance_declaree
-        )
-
-    if dashboard_marche_techniques:
-        lff = lff.filter(
-            pl.col("techniques")
-            .str.split(", ")
-            .list.set_intersection(dashboard_marche_techniques)
-            .list.len()
-            > 0
-        )
-
-    if dashboard_marche_considerations_sociales:
-        lff = lff.filter(
-            pl.col("considerationsSociales")
-            .str.split(", ")
-            .list.set_intersection(dashboard_marche_considerations_sociales)
-            .list.len()
-            > 0
-        )
-
-    if dashboard_marche_considerations_environnementales:
-        lff = lff.filter(
-            pl.col("considerationsEnvironnementales")
-            .str.split(", ")
-            .list.set_intersection(dashboard_marche_considerations_environnementales)
-            .list.len()
-            > 0
-        )
-
-    if dashboard_montant_min is not None:
-        lff = lff.filter(pl.col("montant") >= dashboard_montant_min)
-
-    if dashboard_montant_max is not None:
-        lff = lff.filter(pl.col("montant") <= dashboard_montant_max)
-
-    return lff
+    where_sql, params = dashboard_filters_to_sql(**filter_params)
+    return query_marches(where_sql=where_sql, params=params)
 
 
 def build_org_frame(org_type: str) -> pl.DataFrame:
diff --git a/src/utils/table_sql.py b/src/utils/table_sql.py
index 67d7dcc..f670f80 100644
--- a/src/utils/table_sql.py
+++ b/src/utils/table_sql.py
@@ -1,3 +1,5 @@
+from datetime import datetime, timedelta
+
 import polars as pl
 
 from src.utils import logger
@@ -100,3 +102,107 @@ def sort_by_to_sql(sort_by: list[dict] | None, schema: pl.Schema) -> str:
         fragments.append(f'"{col}" {direction.upper()} NULLS LAST')
 
     return ", ".join(fragments)
+
+
+def dashboard_filters_to_sql(
+    dashboard_year=None,
+    dashboard_acheteur_id=None,
+    dashboard_acheteur_categorie=None,
+    dashboard_acheteur_departement_code=None,
+    dashboard_titulaire_id=None,
+    dashboard_titulaire_categorie=None,
+    dashboard_titulaire_departement_code=None,
+    dashboard_marche_type=None,
+    dashboard_marche_objet=None,
+    dashboard_marche_code_cpv=None,
+    dashboard_marche_considerations_sociales=None,
+    dashboard_marche_considerations_environnementales=None,
+    dashboard_marche_techniques=None,
+    dashboard_marche_innovant=None,
+    dashboard_marche_sous_traitance_declaree=None,
+    dashboard_montant_min=None,
+    dashboard_montant_max=None,
+) -> tuple[str, list]:
+    """Traduit les filtres du tableau de bord en (where_clause, params) DuckDB."""
+    clauses: list[str] = []
+    params: list = []
+
+    if dashboard_year:
+        clauses.append('YEAR("dateNotification") = ?')
+        params.append(int(dashboard_year))
+    else:
+        clauses.append('"dateNotification" > ?')
+        params.append(datetime.now() - timedelta(days=365))
+
+    if dashboard_acheteur_id:
+        clauses.append('"acheteur_id" LIKE ?')
+        params.append(f"%{dashboard_acheteur_id}%")
+    else:
+        if dashboard_acheteur_categorie:
+            clauses.append('"acheteur_categorie" = ?')
+            params.append(dashboard_acheteur_categorie)
+        if dashboard_acheteur_departement_code:
+            placeholders = ", ".join(["?"] * len(dashboard_acheteur_departement_code))
+            clauses.append(f'"acheteur_departement_code" IN ({placeholders})')
+            params.extend(dashboard_acheteur_departement_code)
+
+    if dashboard_titulaire_id:
+        clauses.append('"titulaire_id" LIKE ?')
+        params.append(f"%{dashboard_titulaire_id}%")
+    else:
+        if dashboard_titulaire_categorie:
+            clauses.append('"titulaire_categorie" = ?')
+            params.append(dashboard_titulaire_categorie)
+        if dashboard_titulaire_departement_code:
+            placeholders = ", ".join(["?"] * len(dashboard_titulaire_departement_code))
+            clauses.append(f'"titulaire_departement_code" IN ({placeholders})')
+            params.extend(dashboard_titulaire_departement_code)
+
+    if dashboard_marche_type:
+        clauses.append('"type" = ?')
+        params.append(dashboard_marche_type)
+
+    if dashboard_marche_objet:
+        clauses.append('"objet" ILIKE ?')
+        params.append(f"%{dashboard_marche_objet}%")
+
+    if dashboard_marche_code_cpv:
+        clauses.append('"codeCPV" LIKE ?')
+        params.append(f"{dashboard_marche_code_cpv}%")
+
+    if dashboard_marche_innovant and dashboard_marche_innovant != "all":
+        clauses.append('"marcheInnovant" = ?')
+        params.append(dashboard_marche_innovant)
+
+    if (
+        dashboard_marche_sous_traitance_declaree
+        and dashboard_marche_sous_traitance_declaree != "all"
+    ):
+        clauses.append('"sousTraitanceDeclaree" = ?')
+        params.append(dashboard_marche_sous_traitance_declaree)
+
+    if dashboard_marche_techniques:
+        clauses.append("list_has_any(string_split(\"techniques\", ', '), ?::VARCHAR[])")
+        params.append(list(dashboard_marche_techniques))
+
+    if dashboard_marche_considerations_sociales:
+        clauses.append(
+            "list_has_any(string_split(\"considerationsSociales\", ', '), ?::VARCHAR[])"
+        )
+        params.append(list(dashboard_marche_considerations_sociales))
+
+    if dashboard_marche_considerations_environnementales:
+        clauses.append(
+            "list_has_any(string_split(\"considerationsEnvironnementales\", ', '), ?::VARCHAR[])"
+        )
+        params.append(list(dashboard_marche_considerations_environnementales))
+
+    if dashboard_montant_min is not None:
+        clauses.append('"montant" >= ?')
+        params.append(dashboard_montant_min)
+
+    if dashboard_montant_max is not None:
+        clauses.append('"montant" <= ?')
+        params.append(dashboard_montant_max)
+
+    return " AND ".join(clauses), params
diff --git a/tests/test_dashboard_filters_to_sql.py b/tests/test_dashboard_filters_to_sql.py
new file mode 100644
index 0000000..017248b
--- /dev/null
+++ b/tests/test_dashboard_filters_to_sql.py
@@ -0,0 +1,222 @@
+from datetime import datetime, timedelta
+
+from src.utils.table_sql import dashboard_filters_to_sql
+
+
+def test_no_filters_uses_default_365_day_window():
+    where_sql, params = dashboard_filters_to_sql()
+    assert where_sql == '"dateNotification" > ?'
+    assert len(params) == 1
+    assert isinstance(params[0], datetime)
+    expected = datetime.now() - timedelta(days=365)
+    assert abs((params[0] - expected).total_seconds()) < 2
+
+
+def test_year_filter_overrides_default_window():
+    where_sql, params = dashboard_filters_to_sql(dashboard_year="2025")
+    assert where_sql == 'YEAR("dateNotification") = ?'
+    assert params == [2025]
+
+
+def test_marche_type_equality():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_type="Marché",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "type" = ?'
+    assert params == [2025, "Marché"]
+
+
+def test_innovant_value_all_is_skipped():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_innovant="all",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ?'
+    assert params == [2025]
+
+
+def test_innovant_value_oui_adds_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_innovant="oui",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "marcheInnovant" = ?'
+    assert params == [2025, "oui"]
+
+
+def test_sous_traitance_value_non_adds_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_sous_traitance_declaree="non",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "sousTraitanceDeclaree" = ?'
+    assert params == [2025, "non"]
+
+
+def test_acheteur_id_uses_like_wildcards():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_id="12345678900010",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "acheteur_id" LIKE ?'
+    assert params == [2025, "%12345678900010%"]
+
+
+def test_titulaire_id_uses_like_wildcards():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_titulaire_id="999",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "titulaire_id" LIKE ?'
+    assert params == [2025, "%999%"]
+
+
+def test_marche_objet_uses_case_insensitive_ilike():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_objet="travaux",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "objet" ILIKE ?'
+    assert params == [2025, "%travaux%"]
+
+
+def test_code_cpv_uses_prefix_like():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_code_cpv="4521",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "codeCPV" LIKE ?'
+    assert params == [2025, "4521%"]
+
+
+def test_acheteur_departement_multiple_uses_in_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_departement_code=["75", "92", "93"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? AND "acheteur_departement_code" IN (?, ?, ?)'
+    )
+    assert params == [2025, "75", "92", "93"]
+
+
+def test_acheteur_categorie_adds_clause():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_categorie="Commune",
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "acheteur_categorie" = ?'
+    assert params == [2025, "Commune"]
+
+
+def test_titulaire_categorie_and_departement():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_titulaire_categorie="PME",
+        dashboard_titulaire_departement_code=["35"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        'AND "titulaire_categorie" = ? '
+        'AND "titulaire_departement_code" IN (?)'
+    )
+    assert params == [2025, "PME", "35"]
+
+
+def test_acheteur_id_present_skips_categorie_and_departement():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_acheteur_id="123",
+        dashboard_acheteur_categorie="Commune",
+        dashboard_acheteur_departement_code=["75"],
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "acheteur_id" LIKE ?'
+    assert params == [2025, "%123%"]
+
+
+def test_titulaire_id_present_skips_categorie_and_departement():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_titulaire_id="999",
+        dashboard_titulaire_categorie="PME",
+        dashboard_titulaire_departement_code=["35"],
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "titulaire_id" LIKE ?'
+    assert params == [2025, "%999%"]
+
+
+def test_marche_techniques_uses_list_has_any():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_techniques=["Enchère", "Accord-cadre"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        "AND list_has_any(string_split(\"techniques\", ', '), ?::VARCHAR[])"
+    )
+    assert params == [2025, ["Enchère", "Accord-cadre"]]
+
+
+def test_considerations_sociales_uses_list_has_any():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_considerations_sociales=["Clause sociale"],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        "AND list_has_any(string_split(\"considerationsSociales\", ', '), ?::VARCHAR[])"
+    )
+    assert params == [2025, ["Clause sociale"]]
+
+
+def test_considerations_environnementales_uses_list_has_any():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_marche_considerations_environnementales=["Clause env."],
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? '
+        "AND list_has_any(string_split(\"considerationsEnvironnementales\", ', '), ?::VARCHAR[])"
+    )
+    assert params == [2025, ["Clause env."]]
+
+
+def test_montant_min_only():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_min=1000,
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "montant" >= ?'
+    assert params == [2025, 1000]
+
+
+def test_montant_max_only():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_max=500,
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "montant" <= ?'
+    assert params == [2025, 500]
+
+
+def test_montant_zero_is_a_valid_lower_bound():
+    # 0 est falsy mais reste un filtre valide (distinct de None)
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_min=0,
+    )
+    assert where_sql == 'YEAR("dateNotification") = ? AND "montant" >= ?'
+    assert params == [2025, 0]
+
+
+def test_montant_min_and_max_combined():
+    where_sql, params = dashboard_filters_to_sql(
+        dashboard_year="2025",
+        dashboard_montant_min=100,
+        dashboard_montant_max=1000,
+    )
+    assert where_sql == (
+        'YEAR("dateNotification") = ? AND "montant" >= ? AND "montant" <= ?'
+    )
+    assert params == [2025, 100, 1000]
diff --git a/tests/test_main.py b/tests/test_main.py
index 7f55a02..ae9b36c 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -215,47 +215,6 @@ def test_008_search_to_observatoire(dash_duo: DashComposite):
     )
 
 
-def test_010_observatoire_montant_filter():
-    import datetime
-
-    from src.utils.data import prepare_dashboard_data
-
-    data = pl.DataFrame(
-        {
-            "uid": ["1", "2", "3"],
-            "montant": [100.0, 500.0, 1000.0],
-            "dateNotification": [datetime.date(2025, 1, 1)] * 3,
-        }
-    )
-
-    def apply(min_val=None, max_val=None):
-        return prepare_dashboard_data(
-            data.lazy(),
-            dashboard_year="2025",
-            dashboard_acheteur_id=None,
-            dashboard_acheteur_categorie=None,
-            dashboard_acheteur_departement_code=None,
-            dashboard_titulaire_id=None,
-            dashboard_titulaire_categorie=None,
-            dashboard_titulaire_departement_code=None,
-            dashboard_marche_type=None,
-            dashboard_marche_objet=None,
-            dashboard_marche_code_cpv=None,
-            dashboard_marche_considerations_sociales=None,
-            dashboard_marche_considerations_environnementales=None,
-            dashboard_marche_techniques=None,
-            dashboard_marche_innovant=None,
-            dashboard_marche_sous_traitance_declaree=None,
-            dashboard_montant_min=min_val,
-            dashboard_montant_max=max_val,
-        ).collect()
-
-    assert apply().height == 3
-    assert apply(min_val=400).height == 2  # 500, 1000
-    assert apply(max_val=500).height == 2  # 100, 500
-    assert apply(min_val=200, max_val=600).height == 1  # 500 only
-
-
 def test_009_observatoire_filter_persistence(dash_duo: DashComposite):
     import time