diff --git a/forum/backends/mongodb/contents.py b/forum/backends/mongodb/contents.py
index 99d5c264..489ccd2a 100644
--- a/forum/backends/mongodb/contents.py
+++ b/forum/backends/mongodb/contents.py
@@ -101,7 +101,8 @@ def override_query(self, query: dict[str, Any]) -> dict[str, Any]:
         """
         Override the query with the _type field.
         """
-        query = {**query, "_type": self.content_type}
+        if self.content_type:
+            query = {**query, "_type": self.content_type}
         return super().override_query(query)
 
     def get_list(self, **kwargs: Any) -> Cursor[dict[str, Any]]: