--- a/i18n/de.po	Wed Aug 28 12:08:31 2013 +0200
+++ b/i18n/de.po	Mon Sep 23 12:47:12 2013 +0200
@@ -4534,10 +4534,6 @@
 msgid "view_index"
 msgstr "Index-Seite"
 
-#, python-format
-msgid "violates unique_together constraints (%s)"
-msgstr "Verletzung der unique_together-Einschränkung (%s)"
-
 msgid "visible"
 msgstr "sichtbar"
 

--- a/i18n/en.po	Wed Aug 28 12:08:31 2013 +0200
+++ b/i18n/en.po	Mon Sep 23 12:47:12 2013 +0200
@@ -4423,10 +4423,6 @@
 msgid "view_index"
 msgstr "index"
 
-#, python-format
-msgid "violates unique_together constraints (%s)"
-msgstr "violates unique_together constraints (%s)"
-
 msgid "visible"
 msgstr ""
 

--- a/i18n/es.po	Wed Aug 28 12:08:31 2013 +0200
+++ b/i18n/es.po	Mon Sep 23 12:47:12 2013 +0200
@@ -4582,10 +4582,6 @@
 msgid "view_index"
 msgstr "Inicio"
 
-#, python-format
-msgid "violates unique_together constraints (%s)"
-msgstr "viola el principio (o restricción) de singularidad (%s)"
-
 msgid "visible"
 msgstr "Visible"
 

--- a/i18n/fr.po	Wed Aug 28 12:08:31 2013 +0200
+++ b/i18n/fr.po	Mon Sep 23 12:47:12 2013 +0200
@@ -4599,10 +4599,6 @@
 msgid "view_index"
 msgstr "accueil"
 
-#, python-format
-msgid "violates unique_together constraints (%s)"
-msgstr "violation de contrainte unique_together (%s)"
-
 msgid "visible"
 msgstr "visible"
 

--- a/server/repository.py	Wed Aug 28 12:08:31 2013 +0200
+++ b/server/repository.py	Mon Sep 23 12:47:12 2013 +0200
@@ -1436,11 +1436,9 @@
                 source.update_entity(session, entity)
                 edited.saved = True
             except UniqueTogetherError as exc:
-                etype, rtypes = exc.args
-                problems = {}
-                for col in rtypes:
-                    problems[col] = session._('violates unique_together constraints (%s)') % (','.join(rtypes))
-                raise ValidationError(entity.eid, problems)
+                userhdlr = session.vreg['adapters'].select(
+                    'IUserFriendlyError', session, entity=entity, exc=exc)
+                userhdlr.raise_user_exception()
             self.system_source.update_info(session, entity, need_fti_update)
             if source.should_call_hooks:
                 if not only_inline_rels:

--- a/server/test/unittest_repository.py	Wed Aug 28 12:08:31 2013 +0200
+++ b/server/test/unittest_repository.py	Mon Sep 23 12:47:12 2013 +0200
@@ -558,6 +558,30 @@
             req.create_entity('Affaire', ref=u'AFF02')
             req.execute('SET A duration 10 WHERE A is Affaire')
 
+
+    def test_user_friendly_error(self):
+        from cubicweb.entities.adapters import IUserFriendlyUniqueTogether
+        class MyIUserFriendlyUniqueTogether(IUserFriendlyUniqueTogether):
+            __select__ = IUserFriendlyUniqueTogether.__select__ & is_instance('Societe')
+            def raise_user_exception(self):
+                raise ValidationError(self.entity.eid, {'hip': 'hop'})
+
+        with self.temporary_appobjects(MyIUserFriendlyUniqueTogether):
+            req = self.request()
+            s = req.create_entity('Societe', nom=u'Logilab', type=u'ssll', cp=u'75013')
+            self.commit()
+            with self.assertRaises(ValidationError) as cm:
+                req.create_entity('Societe', nom=u'Logilab', type=u'ssll', cp=u'75013')
+            self.assertEqual(cm.exception.errors, {'hip': 'hop'})
+            self.rollback()
+            req.create_entity('Societe', nom=u'Logilab', type=u'ssll', cp=u'31400')
+            with self.assertRaises(ValidationError) as cm:
+                s.cw_set(cp=u'31400')
+            self.assertEqual(cm.exception.entity, s.eid)
+            self.assertEqual(cm.exception.errors, {'hip': 'hop'})
+            self.rollback()
+
+
 class SchemaDeserialTC(CubicWebTC):
 
     appid = 'data-schemaserial'