Disclaimer: I grew up in Germany/Austria and find the topic of Europeqn demographics quite intriguing
As far as France and immigrants go, I'm not sure relevant studies are available (since France has very specific policies about not mentionning race/origin in its official data). But My intuition is that the role of the immigrant population is overrated. Mostly because the keyword here is "recent" and while France has a rather large population of second or third generation immigrants, the recent immigrant population is probably not much higher than anywhere in Europe.
Stop giving these freebies and fertility rates will drop in no time.
The question is , should we encourage it? in the long run ,it doesnt make sense. We often hear on the radio here how Germans dont make babies anymore and it will doom Germany. I dont think so, one country doesnt need perpetual population growth in order to survive, i believe Germans are smarter on these issues.
Can a country with perpetually declining and aging population survive? In what form?
France has very active policies in place to promote large families, which is why if you run into a French couple with children they'll often have three or more instead of just one or two.
More conservative societies see a steeper decline in birthrate as women participation in the workforce increases.
That's why France has one of the highest birthrate in Europe for instance.