Thanks for the responses.
Without any testing, that seems like a good way to address that. +2 culture prior to any buildings really could add up quickly when your puppets aren't raising culture costs. Cutting it down keeps it reasonable while still giving France an interesting perk.
If you are going for something other than culture, it is a minor consideration. If you're going for the culture victory, this is definitely a factor. I think I will give a puppet empire with France a run.