--- a/web/views/formrenderers.py	Wed Sep 16 17:07:26 2015 +0200
+++ b/web/views/formrenderers.py	Wed Sep 16 17:22:41 2015 +0200
@@ -37,6 +37,8 @@
 
 from warnings import warn
 
+from six import text_type
+
 from logilab.mtconverter import xml_escape
 from logilab.common.registry import yes
 
@@ -119,7 +121,7 @@
             data.insert(0, errormsg)
         # NOTE: we call unicode because `tag` objects may be found within data
         #       e.g. from the cwtags library
-        w(''.join(unicode(x) for x in data))
+        w(''.join(text_type(x) for x in data))
 
     def render_content(self, w, form, values):
         if self.display_progress_div: