The theme’s translations are contributed and updated voluntarily. Unfortunately, for the French language there’s currently no one maintaining or updating the translation file. If you want to volunteer to update the translation, I can send you the updated fr_FR.po file.
This free Support Forum relies on contributions from our support staffs and fellow Graphene themes users. While we endeavour to provide adequate and timely support, due to its voluntary nature responses are not guaranteed and may be delayed.
If you require urgent assistance, you may like to consider our Priority Support option.