There are many tutorials online, and I suspect some can be translated into French. I can’t speak to a personal tutor, but honestly, switching to Dorico from Finale is much easier, I suspect, than learning Dorico outright without having worked in Finale. I made the switch in about a month, mostly by reading the manual and then composing a new piece so that I could learn how to do things that came up in real-world use. I’d start by reading the manual and watching some of the tutorials. I’m sure, as mentioned, some are in French or can be autotranslated on the fly. Good luck!

Merci David, vous êtes encourageant.

There is Groupe des utilisateurs francophones de Dorico on FaceBook for French Dorico users.