diff --git a/pybis/src/python/tests/test_tag.py b/pybis/src/python/tests/test_tag.py
index 9308f3b0560c72a693f7e402abd2bb3fcb602455..71f64706cd471e3276887b3e775916562335853a 100644
--- a/pybis/src/python/tests/test_tag.py
+++ b/pybis/src/python/tests/test_tag.py
@@ -17,7 +17,7 @@ def test_crud_tag(openbis_instance):
 
     assert tag.code == tag_name
     assert tag.description == description
-    assert tag.permId is None
+    assert tag.permId == ''
 
     tag.save()