you can add :
$LNG['rank_hits_in'] = "Classement par entrée";
$LNG['rank_hits_out'] = "Classement par sortie";
$LNG['user_cp_banner_error_max_dimensions'] = 'Vous avez dépassé les dimmensions maximales!';
$LNG['user_cp_banner_error_max_filesize'] = 'Vous avez dépassé la taille maximale!'...
it's because, i'll try the english install, and it work, then i looked the french file and the word S'incrire say me : php and the caracter ' , so try to escape it to see if it's work, and the install worked :)
Same error for the regular licence without the branding free.
Fatal error: Database error in "/public_html/install/index.php" on line 509
Erreur de syntaxe près de 'inscrire', 'http://.net/?a=join',1)' à la ligne 2 in public_html/sources/sql/mysql.php on line 88