Good evening Ernest,
I placed the file in the wordpress folder and everything works fine.
I hope that the file will not be overwritten during the next update of WordPress. But at each update I find the translated files so I think it should not be a problem.
I will wait for the next update of the plugin to translate the sentences that can’t be translated for the moment and I will send you the Fr file.
For future updates of the plugin, if new features with new sentences are available, I will also translate them with each new update.
Regards.
Domi
Ps : And thanks for your help and the possibility to translate the new sentences in polylang!