As promised, here is the french translation. The xml file is a product to install. It will replace english phrases. Anybody who wants to improve the translation can do it
In gal_admin.php some phrases are still hardcoded :
-l.201 : "Add new"
-l.510 : "Mantainence"
PS : I couldn't test all the translations because i'm only using the lite version, where as phrases seem to be for lite and pro versions.