--- a/_exceptions.py	Tue Nov 27 11:38:03 2012 +0100
+++ b/_exceptions.py	Tue Nov 27 12:24:56 2012 +0100
@@ -103,6 +103,10 @@
         except Exception, ex:
             return str(ex)
 
+class Forbidden(SecurityError):
+    """raised when a user tries to perform a forbidden action
+    """
+
 # source exceptions ###########################################################
 
 class EidNotInSource(SourceException):

--- a/i18n/de.po	Tue Nov 27 11:38:03 2012 +0100
+++ b/i18n/de.po	Tue Nov 27 12:24:56 2012 +0100
@@ -864,6 +864,11 @@
 msgid "This WorkflowTransition"
 msgstr "Dieser Workflow-Übergang"
 
+msgid ""
+"This action is forbidden. If you think it should be allowed, please contact "
+"the site administrator."
+msgstr ""
+
 msgid "This entity type permissions:"
 msgstr "Berechtigungen für diesen Entitätstyp"
 

--- a/i18n/en.po	Tue Nov 27 11:38:03 2012 +0100
+++ b/i18n/en.po	Tue Nov 27 12:24:56 2012 +0100
@@ -840,6 +840,11 @@
 msgid "This WorkflowTransition"
 msgstr "This workflow-transition"
 
+msgid ""
+"This action is forbidden. If you think it should be allowed, please contact "
+"the site administrator."
+msgstr ""
+
 msgid "This entity type permissions:"
 msgstr ""
 

--- a/i18n/es.po	Tue Nov 27 11:38:03 2012 +0100
+++ b/i18n/es.po	Tue Nov 27 12:24:56 2012 +0100
@@ -865,6 +865,11 @@
 msgid "This WorkflowTransition"
 msgstr "Esta transición de Workflow"
 
+msgid ""
+"This action is forbidden. If you think it should be allowed, please contact "
+"the site administrator."
+msgstr ""
+
 msgid "This entity type permissions:"
 msgstr "Permisos para este tipo de entidad:"
 

--- a/i18n/fr.po	Tue Nov 27 11:38:03 2012 +0100
+++ b/i18n/fr.po	Tue Nov 27 12:24:56 2012 +0100
@@ -865,6 +865,13 @@
 msgid "This WorkflowTransition"
 msgstr "Cette transition workflow"
 
+msgid ""
+"This action is forbidden. If you think it should be allowed, please contact "
+"the site administrator."
+msgstr ""
+"Cette action est interdite. Si toutefois vous pensez qu'elle devrait être "
+"autorisée, veuillez contacter l'administrateur du site."
+
 msgid "This entity type permissions:"
 msgstr "Permissions pour ce type d'entité"
 

--- a/web/application.py	Tue Nov 27 11:38:03 2012 +0100
+++ b/web/application.py	Tue Nov 27 12:24:56 2012 +0100
@@ -34,7 +34,8 @@
 
 from cubicweb import set_log_methods, cwvreg
 from cubicweb import (
-    ValidationError, Unauthorized, AuthenticationError, NoSelectableObject,
+    ValidationError, Unauthorized, Forbidden,
+    AuthenticationError, NoSelectableObject,
     BadConnectionId, CW_EVENT_MANAGER)
 from cubicweb.dbapi import DBAPISession, anonymous_session
 from cubicweb.web import LOGGER, component
@@ -470,6 +471,11 @@
                                        'If you think you should, please contact the site administrator.')
             req.status_out = httplib.UNAUTHORIZED
             result = self.error_handler(req, ex, tb=False)
+        except Forbidden, ex:
+            req.data['errmsg'] = req._('This action is forbidden. '
+                                       'If you think it should be allowed, please contact the site administrator.')
+            req.status_out = httplib.FORBIDDEN
+            result = self.error_handler(req, ex, tb=False)
         except (BadRQLQuery, RequestError), ex:
             result = self.error_handler(req, ex, tb=False)
         ### pass through exception