Hello ! I am a French canadian, but we are currently living in the US. Right now, my kids are learning both Engligh and French as a “first” language. It’s true that there’s no CM French curriculum, but it’s possible to find living books in French. Here is a website with a nice list imo :
http://petitshomeschoolers.blogspot.com/2014/03/charlotte-mason-liste-francaise-de.html
There’s also a list of science and history books on the same site. We mostly follow a Charlotte Mason English curriculum, complemented with French phonics and literature. Also, French is a very complex language with lots of grammatical rules, so I think that I some point you would also need a more formal writing curriculum. As of now, I haven’t found one that I love though.
Hope it helps and feel free to ask if you have any questions, Good luck !