Thank you for the help.
I've made some small changes and put your work here:
branches/lang/XMB_1_9_12/French.lang.php
If you want to continue improving the file, here is some feedback.
These are still English:
admin_main_settings10
admin_main_settings9
attach_delete_ays
attach_delete_done
coppa_directions
editprofile_lockout
editprofile_loginfaildate
editprofile_loginfails
editprofile_sessfaildate
editprofile_sessfails
google_captcha_directions
textlostpwnote2
textnopassword