diff --git a/tryton/common/timedelta.py b/tryton/common/timedelta.py
index 455df339ff..208083b2cb 100644
--- a/tryton/common/timedelta.py
+++ b/tryton/common/timedelta.py
@@ -70,7 +70,7 @@ def format(value, converter=None):
         if not any(values[-3:]):
             # Add space if no time
             text += ' '
-        text += ('%.6f' % value)[1:]
+        text += locale.format_string('%.6f', value)[1:]
     return text