diff --git a/product/CMFCategory/Category.py b/product/CMFCategory/Category.py
index 65852769605d8d7e4dac24dc60c17e18a91a5bae..84eab42b2bbe32fdc57c4a43f4d9c0764ce5c93b 100644
--- a/product/CMFCategory/Category.py
+++ b/product/CMFCategory/Category.py
@@ -365,7 +365,9 @@ class Category(Folder):
       """
       if not base:
         base = '' # Make sure we get a meaningful base
-      if base:
+      elif isinstance(base, str):
+        base = base + '/'
+      elif base:
         base = self.getBaseCategoryId() + '/' # Make sure we get a meaningful base
       url_list = []
       for value in self.getCategoryChildValueList(recursive=recursive,