Such an interesting subject, and again one that shows very different politicies and attitudes from different countries.
France has long realised that it is not replacing itself - and that the pyramid of ages is inversing- so have long had a policy of increasing child allowance and other support with each child.
So the first and second child get a small amount, and more for the 3rd, and 4th , and so on - always increasing in value, per child.
With my 6th Formers we used to study a book called 'les petits enfants du siècle' - the story of a teenager who lives in a rough 'banlieue' (yes, funny too that in the UK 'suburb = 'good'- whereas in France 'banlieue = 'bad'- interesting historical reasons, due to early industrialisation in UK) - and has more and more sibblings so family can afford a new settee, new TV, etc, and then, eventually, the big prize, a car! In the 60s (or 70s) can't remember.
Of course also causing controversy still now- as the middle and well educated classes stick to 1, 2 or none, and the poorer, less educated, and yes (the reality) immigrants, have large families and require a lot of support.