diff --git a/api/factories/file_factory.py b/api/factories/file_factory.py
index 8c989e6b5..796113e10 100644
--- a/api/factories/file_factory.py
+++ b/api/factories/file_factory.py
@@ -196,7 +196,7 @@ def _build_from_remote_url(
         raise ValueError("Invalid file url")
 
     mime_type, filename, file_size = _get_remote_file_info(url)
-    extension = mimetypes.guess_extension(mime_type) or "." + filename.split(".")[-1] if "." in filename else ".bin"
+    extension = mimetypes.guess_extension(mime_type) or ("." + filename.split(".")[-1] if "." in filename else ".bin")
 
     file_type = FileType(mapping.get("type", "custom"))
     file_type = _standardize_file_type(file_type, extension=extension, mime_type=mime_type)