diff --git a/addons/website_sale/controllers/main.py b/addons/website_sale/controllers/main.py
index af25f578802..b4a93597630 100644
--- a/addons/website_sale/controllers/main.py
+++ b/addons/website_sale/controllers/main.py
@@ -464,7 +464,7 @@ class website_sale(http.Controller):
         # set data
         if isinstance(data, dict):
             query = dict((prefix + field_name, data[prefix + field_name])
-                for field_name in all_fields if data.get(prefix + field_name))
+                for field_name in all_fields if prefix + field_name in data)
         else:
             query = dict((prefix + field_name, getattr(data, field_name))
                 for field_name in all_fields if getattr(data, field_name))
@@ -482,7 +482,7 @@ class website_sale(http.Controller):
         if not remove_prefix:
             return query
 
-        return dict((field_name, data[prefix + field_name]) for field_name in all_fields if data.get(prefix + field_name))
+        return dict((field_name, data[prefix + field_name]) for field_name in all_fields if prefix + field_name in data)
 
     def checkout_form_validate(self, data):
         cr, uid, context, registry = request.cr, request.uid, request.context, request.registry