@Alelm: impartial doesn't mean on your side. You keep telling you understand the rules but then demanding otherwise. As I said at in my opening post, you are free to consult staff or whoever you want on the matter if you distrust what I'm saing. I opened this thread to clear the misunderstandings here.
@Clara: No, you have to add that to all images, you can take your time of course. You can simply copy and paste something like
== Fonte == Immagine tratta da un videogioco del franchise di Tekken. Inizialmente caricata sulla [https://tekken.fandom.com/fr/ TekkenPedia (FR)]. == Licenza == Template fair use
A banner on the main page is not enough and you have to add a link to the FR wiki, writing the name is too ambiguos. You also need a template for the fair use, if you don't have any you can copy the one from the central wiki or some other wiki. You don't have to add the link to the specific file for the images you already have, if you want you can do that for the future images.