diff --git a/weboob/core/bcall.py b/weboob/core/bcall.py
index b707f9a1..c44b015a 100644
--- a/weboob/core/bcall.py
+++ b/weboob/core/bcall.py
@@ -32,7 +32,7 @@ class CallErrors(Exception):
     def __init__(self, errors):
         Exception.__init__(self, u'These errors have been raised in backend threads '\
                            '(use --debug option to print backtraces):\n%s' % (
-            u'\n'.join((u' * %s: %s%s' % (backend, error, backtrace + '\n'
+            u'\n'.join((u' * %s: %s%s' % (backend, repr(error), backtrace + '\n'
                                           if logging.root.level == logging.DEBUG else ''))
                        for backend, error, backtrace in errors)))
         self.errors = copy(errors)