diff --git a/keystone/identity/controllers.py b/keystone/identity/controllers.py
index 39b0cec248..cc8b283566 100644
--- a/keystone/identity/controllers.py
+++ b/keystone/identity/controllers.py
@@ -60,7 +60,7 @@ def get_projects_for_token(self, context, **kw):
         try:
             token_ref = self.token_api.get_token(context['token_id'])
         except exception.NotFound as e:
-            LOG.warning('Authentication failed: %s' % e)
+            LOG.warning(_('Authentication failed: %s') % e)
             raise exception.Unauthorized(e)
 
         user_ref = token_ref['user']