diff --git a/.gitignore b/.gitignore
index 2bff50a..10dc959 100644
--- a/.gitignore
+++ b/.gitignore
@@ -12,3 +12,9 @@ build
 **/decp.duckdb.tmp
 **/decp.duckdb.lock
 **/schema.cache.json
+
+# Runtime databases (never commit)
+users.sqlite
+*.sqlite
+!tests/*.sqlite
+!tests/**/*.sqlite
diff --git a/src/backup/cli.py b/src/backup/cli.py
index c7b4a75..4046dd2 100644
--- a/src/backup/cli.py
+++ b/src/backup/cli.py
@@ -1,4 +1,5 @@
 import argparse
+import logging
 import os
 import sys
 from datetime import datetime, timezone
@@ -7,6 +8,8 @@ from src.backup import service
 from src.backup.config import load_config
 from src.backup.storage import S3Storage
 
+logger = logging.getLogger(__name__)
+
 
 def main(argv=None, env=None, storage=None) -> int:
     env = env if env is not None else os.environ
@@ -24,9 +27,14 @@ def main(argv=None, env=None, storage=None) -> int:
     now = datetime.now(timezone.utc)
 
     if args.cmd == "backup":
-        key = service.run_backup(config, storage, now)
-        print(f"sauvegarde créée : {key}")
-        return 0
+        try:
+            key = service.run_backup(config, storage, now)
+            print(f"sauvegarde créée : {key}")
+            return 0
+        except Exception as exc:
+            logger.error("Échec de la sauvegarde : %s", exc, exc_info=True)
+            print(f"Erreur : {exc}", file=sys.stderr)
+            return 1
 
     if args.cmd == "list":
         backups = service.list_backups(config, storage)
diff --git a/src/backup/service.py b/src/backup/service.py
index 08ee401..371faca 100644
--- a/src/backup/service.py
+++ b/src/backup/service.py
@@ -1,3 +1,4 @@
+import logging
 import os
 import tempfile
 from datetime import datetime
@@ -8,6 +9,8 @@ from src.backup.config import BackupConfig
 from src.backup.rotation import select_retained
 from src.backup.storage import Storage
 
+logger = logging.getLogger(__name__)
+
 
 def _dated_keys(storage: Storage, prefix: str) -> list[tuple[str, datetime]]:
     dated: list[tuple[str, datetime]] = []
@@ -30,6 +33,7 @@ def run_backup(config: BackupConfig, storage: Storage, now: datetime) -> str:
     for k, ts in dated:
         if ts not in retained:
             storage.delete(k)
+    logger.info("Sauvegarde créée : %s", key)
     return key
 
 
@@ -57,6 +61,7 @@ def restore(config: BackupConfig, storage: Storage, key: str, now: datetime) ->
             backup_copy.write_bytes(db_path.read_bytes())
         os.replace(tmp_path, db_path)
     except Exception:
+        logger.error("Échec de la restauration depuis %s", key, exc_info=True)
         tmp_path.unlink(missing_ok=True)
         raise
     return backup_copy
diff --git a/src/backup/snapshot.py b/src/backup/snapshot.py
index eb3660e..e6dbc9d 100644
--- a/src/backup/snapshot.py
+++ b/src/backup/snapshot.py
@@ -5,6 +5,8 @@ from pathlib import Path
 
 
 def make_snapshot(db_path: Path) -> bytes:
+    if not db_path.exists():
+        raise FileNotFoundError(f"Base de données introuvable : {db_path}")
     with tempfile.NamedTemporaryFile(suffix=".sqlite", delete=False) as tmp:
         tmp_path = Path(tmp.name)
     try:
diff --git a/src/backup/storage.py b/src/backup/storage.py
index 0e7b734..203cb6c 100644
--- a/src/backup/storage.py
+++ b/src/backup/storage.py
@@ -14,8 +14,13 @@ class Storage(Protocol):
 
 class S3Storage:
     def __init__(
-        self, bucket, endpoint_url, access_key, secret_key, region="us-east-1"
-    ):
+        self,
+        bucket: str,
+        endpoint_url: str | None,
+        access_key: str,
+        secret_key: str,
+        region: str = "us-east-1",
+    ) -> None:
         self._bucket = bucket
         self._client = boto3.client(
             "s3",
diff --git a/tests/backup/test_cli.py b/tests/backup/test_cli.py
index fa4db01..a324238 100644
--- a/tests/backup/test_cli.py
+++ b/tests/backup/test_cli.py
@@ -33,3 +33,14 @@ def test_backup_then_list(tmp_path, capsys):
     out = capsys.readouterr().out
     assert "users-" in out
     assert len(storage.objects) == 1
+
+
+def test_restore(tmp_path):
+    env = _env(tmp_path)
+    storage = FakeStorage()
+    # Create a backup first
+    assert cli.main(["backup"], env=env, storage=storage) == 0
+    key = next(iter(storage.objects))
+    # Restore it
+    ret = cli.main(["restore", key], env=env, storage=storage)
+    assert ret == 0
diff --git a/users.sqlite b/users.sqlite
deleted file mode 100644
index ef84536..0000000
Binary files a/users.sqlite and /dev/null differ