diff --git a/swh/loader/mercurial/identify.py b/swh/loader/mercurial/identify.py
--- a/swh/loader/mercurial/identify.py
+++ b/swh/loader/mercurial/identify.py
@@ -314,7 +314,7 @@
     """Return the SWHID of the given path."""
     return CoreSWHID.from_string(
         identify_object(
-            "directory", follow_symlinks=True, exclude_patterns=[".hg"], obj=str(path)
+            "directory", follow_symlinks=True, exclude_patterns=[b".hg"], obj=str(path)
         )
     )