diff --git a/src/govoplan_files/backend/storage/files.py b/src/govoplan_files/backend/storage/files.py
index 67764c6..072e1d8 100644
--- a/src/govoplan_files/backend/storage/files.py
+++ b/src/govoplan_files/backend/storage/files.py
@@ -596,21 +596,31 @@ def _asset_visibility_query_for_user(
         if owner_type == "group" and owner_id:
             query = query.filter(FileAsset.owner_group_id == owner_id)
     if campaign_id:
-        query = query.join(FileShare, FileShare.file_asset_id == FileAsset.id).filter(
+        campaign_share = exists().where(
             FileShare.tenant_id == tenant_id,
+            FileShare.file_asset_id == FileAsset.id,
             FileShare.target_type == "campaign",
             FileShare.target_id == campaign_id,
             effective_file_share_clause(),
         )
+        query = query.filter(campaign_share)
     elif not is_admin and not owner_type:
         group_ids = user_group_ids(session, tenant_id=tenant_id, user_id=user_id)
-        query = query.outerjoin(FileShare, FileShare.file_asset_id == FileAsset.id).filter(
+        active_share = exists().where(
+            FileShare.tenant_id == tenant_id,
+            FileShare.file_asset_id == FileAsset.id,
+            effective_file_share_clause(),
+            or_(
+                (FileShare.target_type == "user") & (FileShare.target_id == user_id),
+                (FileShare.target_type == "group") & (FileShare.target_id.in_(group_ids)),
+                (FileShare.target_type == "tenant") & (FileShare.target_id == tenant_id),
+            )
+        )
+        query = query.filter(
             or_(
                 (FileAsset.owner_type == "user") & (FileAsset.owner_user_id == user_id),
                 (FileAsset.owner_type == "group") & (FileAsset.owner_group_id.in_(group_ids)),
-                effective_file_share_clause() & (FileShare.target_type == "user") & (FileShare.target_id == user_id),
-                effective_file_share_clause() & (FileShare.target_type == "group") & (FileShare.target_id.in_(group_ids)),
-                effective_file_share_clause() & (FileShare.target_type == "tenant") & (FileShare.target_id == tenant_id),
+                active_share,
             )
         )
     if path_prefix:
@@ -639,7 +649,7 @@ def _asset_visibility_query_for_user(
             CampaignAttachmentUse.use_stage == "sent",
         )
         query = query.filter(sent_use_exists if audit_relevant else ~sent_use_exists)
-    return query.distinct()
+    return query
 
 
 def count_assets_for_user(
diff --git a/tests/test_share_lifecycle.py b/tests/test_share_lifecycle.py
index 256d09c..55326ad 100644
--- a/tests/test_share_lifecycle.py
+++ b/tests/test_share_lifecycle.py
@@ -5,6 +5,7 @@ from datetime import timedelta
 from unittest.mock import patch
 
 from sqlalchemy import create_engine
+from sqlalchemy.dialects import postgresql
 from sqlalchemy.orm import sessionmaker
 
 from govoplan_access.backend.db.models import Account, Group, User
@@ -13,6 +14,7 @@ from govoplan_core.db.base import Base
 from govoplan_files.backend.db.models import FileAsset, FileShare
 from govoplan_files.backend.storage.common import FileStorageError, utcnow
 from govoplan_files.backend.storage.files import (
+    _asset_visibility_query_for_user,
     get_asset_for_user,
     list_file_shares,
     revoke_file_share,
@@ -214,6 +216,22 @@ class FileShareLifecycleTests(unittest.TestCase):
                 expires_at=utcnow() - timedelta(seconds=1),
             )
 
+    @patch(
+        "govoplan_files.backend.storage.files.user_group_ids",
+        return_value=[],
+    )
+    def test_visibility_query_is_postgresql_json_safe(self, _groups) -> None:
+        query = _asset_visibility_query_for_user(
+            self.session,
+            tenant_id=TENANT_ID,
+            user_id=RECIPIENT_ID,
+        )
+
+        compiled = str(query.statement.compile(dialect=postgresql.dialect()))
+
+        self.assertNotIn("SELECT DISTINCT", compiled.upper())
+        self.assertIn("EXISTS", compiled.upper())
+
 
 if __name__ == "__main__":
     unittest.main()