Hello @maroin
Right now we don’t have any active GD translator lead for French locale to help us fixing the translations. You should join our translation team 🙂 and if you are interested to be GD Translator lead please check our Translator’s Handbook for more details.
Then help us over here where you can fix up translated strings in your language:
https://translate.wordpress.org/projects/wp-plugins/geodirectory
French locale team is a little bit strict than other locale team. Make sure to get in touch/ be friendly to them and follow their rules to get your suggestion approve.
Let me know if you have any question. You can also contact me on https://make.wordpress.org/chat/. Use your wordpress.org user account to make an account and send me a message to @ismiaini.