Considering that Fallout diverges from our timeline in the 50's, separatist movements would have died with America's annexation, strong rule and the bombs.
French issued from vaults or who simply survived the Great War wouldn't give a damn about having their french-canadian own territory, or they wouldn't give a damn about fighting with the English Canadians for culture and language. They'd be fighting for resources.
Like in America, canadians, both French and English, would be fighting amongst themselves for resources, regardless of language and culture.
I actually doubt that this would be the case... entirely.
To be honest, whatever divisions you had between the French and English speaking peoples of Canada... they would likely have been annihilated by the sudden annexation of their entire nation by the United States. Activists were gunned down in the streets... protesters brutally murdered. If -that- isn't the kind of oppressive force that spawns revolutionary movements... I don't know what is.
But at the same time, why would they bother to revolt after the Great War? What are they revolting against? Assuming they didn't get nuked off the face of the planet... which they probably wouldn't have (any more so than the rest of North America)... who would stop them from simply reforming themselves as Canada, if they so desired? I seriously doubt that there is any real military presence in the area which has survived for 200 years continuing to force them to serve United States ends.
If anyone, it would be the Enclave... and the Enclave doesn't really deal with those who have been exposed to the desert radiation and mutations.
It just wouldn't make any sense to have a revolution, as far as I'm concerned.
A game set in Canada would be interesting. Maybe one set across the whole of North America, even.
But I just can't see any really sustainable plot for a revolution