As I understand it, the French mindset is that, as long as you are willing to speak French, and to adopt the French way of thinking --- liberté, égalité, fraternité --- as well as French customs and social norms, anyone can be French. It's far from being an ethnostate. They do not even ask about race when they take their census.
Adopting the customs and social norms of the host country --- what a concept! Heaven help you if you don't say "bonjour" to the shopkeeper when you enter a store, or fail to send New Year's greetings to everyone in your social circle.