Two different translations for the same language
French translators found a translation bug in the main menu of GNOME (present in edgy, feisty and gusty), the wrong package seemed to be gnome-desktop but it was right in upstream and Rosetta. After some investigation, I found not one but two PO files for the same French translation:
$ dpkg -S gnome-desktop-
fr_FR is unuseful, I deleted fr_FR one and translation is correct now!
Maybe some other packages have the same problem because my fr_FR directory contains (on Feisty):