--- a/src/pyams_content/shared/common/zmi/rename.py	Wed Dec 12 22:58:37 2018 +0100
+++ b/src/pyams_content/shared/common/zmi/rename.py	Thu Dec 13 09:44:21 2018 +0100
@@ -121,3 +121,6 @@
     name = event.data.get('__name__')
     if not name:
         event.form.widgets.errors += (Invalid(_("You must provide an URL for this item!")),)
+    target = event.form.context.__parent__.get(name)
+    if (target is not None) and (target is not event.form.context):
+        event.form.widgets.errors += (Invalid(_("Selected URL already exists!")),)