diff --git a/auth/permissions.py b/auth/permissions.py
index bdc460786..e53dd6fe8 100644
--- a/auth/permissions.py
+++ b/auth/permissions.py
@@ -269,7 +269,7 @@ def on_identity_loaded(sender, identity):
     repo_grant = _RepositoryNeed(token_data.repository.namespace_user.username,
                                  token_data.repository.name,
                                  token_data.role.name)
-    logger.debug('Delegate token added permission: {0}'.format(repo_grant))
+    logger.debug('Delegate token added permission: %s', repo_grant)
     identity.provides.add(repo_grant)
 
   elif identity.auth_type == 'signed_grant':