The reason France's math output is so stellar is because of the controversial grand école system - pretty much every great French mathematician you can name cam

The reason France's math output is so stellar is because of the controversial grand école system - pretty much every great French mathematician you can name came out of one of the top 2 schools. It's very elitist (and the elitism is misplaced since the system as well as the schools are virtually unknown outside of France compared to, say, the Ivies) but it does have results.