diff --git a/product/ERP5Type/Core/StandardProperty.py b/product/ERP5Type/Core/StandardProperty.py
index 5e9a7c67369543646a64ccf9eae6801c64391c17..d87d49d98836acec96494fc51a5a6f29a79d7bff 100644
--- a/product/ERP5Type/Core/StandardProperty.py
+++ b/product/ERP5Type/Core/StandardProperty.py
@@ -79,7 +79,7 @@ class StandardProperty(XMLObject):
       if category.startswith('elementary_type/'):
         return category.split('elementary_type/')[1]
 
-    return None
+    return getattr(self, 'elementary_type', None)
 
   getStorageId = BaseGetter('getStorageId', 'storage_id', 'string')