diff --git a/addons/website_form/controllers/main.py b/addons/website_form/controllers/main.py
index 978692e894a..fd42ef8da0b 100644
--- a/addons/website_form/controllers/main.py
+++ b/addons/website_form/controllers/main.py
@@ -142,7 +142,7 @@ class WebsiteForm(http.Controller):
 
             # If it's a custom field
             elif field_name != 'context':
-                data['custom'] += "%s : %s\n" % (field_name.decode('utf-8'), field_value)
+                data['custom'] += u"%s : %s\n" % (field_name, field_value)
 
         # Add metadata if enabled
         environ = request.httprequest.headers.environ