Quite striking and strange for a modern mathematician to read the following, from Condorcet’s 1787 lectures to the Lycee:
It is to French mathematicians that we owe the theory of probability calculus. This is perhaps worth saying. Other nations, and often even Frenchmen themselves, have reproached us for lacking the gift of invention, granting us only the ability to perfect other people’s discoveries…
Quomodocumque 
So now we know that all the French greats were built out of spite.
As many other things, French mathematics has had its ups and downs historically… In his inimitable style, André Weil more or less claims that at the time of his PhD (early 1920’s), the only good mathematicians (apart from those of his generation) remaining in France were É. Cartan, and J. Hadamard. One must certainly add at least P. Lévy, but altogether French mathematics was definitely not as good as it has been in the last 60 years.
I guess this is the math version of the sports worlds `No one respected us, no one believed in us.’
Interesting quote. The Indian idea of maya came immediately to my mind: looking across the generations, the notion of French mathematics as underdog is illusory. (But perhaps I don’t fully grasp the idea of maya–it’s been said that only the truly aged do.)
Didn’t the French lose many mathematicians in WWI (1914-1918)?
It lost an enormous number of its most talented students – if I am not mistaken, 40% in the entering classes at the top schools in some years died of battle-related causes. What is remarkable is that French mathematics managed to flourish after this.