That seems to be the assumption, but I have not seen any data on it, and I suspect "French" birth rates are in fact up, and in fact higher than in almost all of Europe. The centralized French government when it really puts its mind to something, is rather effective. Maybe V knows more.
Yes, it seems to be the assumption, but one based on reports from the world press. France is approaching the tipping point, at which it will no longer be able to assert it's history and it's grandeur to either keep order or preserve the traditional values of daily life. What can we assume will happen in France? Muslims will have a louder and louder voice, and will soon be telling France how to reform itself in the Sharia traditions.