Deport where? Aren't most of these people French citizens born in France?
Is Devil's Island still in use? Probably a rhetorical question. They won't deport anybody.
Is a person born in France automatically a citizen? What about children of illegals? I think our laws are more liberal than theirs.
How about Devils Island. I think they still own that.
"Aren't most of these people French citizens born in France?"
You're being too practical. Try thinking with style, like a Frenchie.
A country without a constitution to guide it, can pretty much do what ever the leader wants to do. There are many countries around the world that export their troublemaking citizens to another country.
I don't see this happening, but it is more because of a lack of will on the part of the leaders of France rather then any legal restriction.