Drupal 7 says that it is in 7.14 translation version instead of 7.15

Hello,

I update drupal7 from 7.14 to 7.15

All seams to work ok.

But for the language 7.15.fr.po (french)
i install it from manual mode
everything seamed to be ok but
drupal say me that i use à 7.14 version
of the translation.

How can i say to drupal that he is really in 7.15 ?
or what can i verify please ?

Sorry for my bad english.