So, that's the way I've done it (but without changing extension jar to zip, because 7-zip can open jar files).
I'm surprised with the uploaded file because at home, it works (and directly in french when I run it which is not the case with ejs_users_ntnu_fkh_magnetdeflect_fr.jar (I have to select french translation by right clicking)).
I'll upload it again (let me know if it's the good one).
But, for the moment, none of them wants to load in french when I open it in a browser ;o((
And I cannot right click to change the langage ;o((