diff --git a/openerp/report/report_sxw.py b/openerp/report/report_sxw.py
index 79f4d32639f..1ceb73e18b6 100644
--- a/openerp/report/report_sxw.py
+++ b/openerp/report/report_sxw.py
@@ -78,7 +78,7 @@ class _format(object):
 class _float_format(float, _format):
     def __init__(self,value):
         super(_float_format, self).__init__()
-        self.val = value
+        self.val = value and str(value) or str(0.0)
 
     def __str__(self):
         digits = 2
@@ -86,7 +86,7 @@ class _float_format(float, _format):
             digits = self._field.digits[1]
         if hasattr(self, 'lang_obj'):
             return self.lang_obj.format('%.' + str(digits) + 'f', self.name, True)
-        return str(self.val)
+        return self.val
 
 class _int_format(int, _format):
     def __init__(self,value):