diff --git a/openerp/addons/base/ir/ir_qweb.py b/openerp/addons/base/ir/ir_qweb.py
index 10a7f6d2b09..60f5e71b341 100644
--- a/openerp/addons/base/ir/ir_qweb.py
+++ b/openerp/addons/base/ir/ir_qweb.py
@@ -181,6 +181,8 @@ class QWeb(orm.AbstractModel):
         val = self.eval(expr, qwebcontext)
         if isinstance(val, unicode):
             return val.encode("utf8")
+        if val is False or val is None:
+            return ''
         return str(val)
 
     def eval_format(self, expr, qwebcontext):