It's not reported as centrally as other numbers so it's hard to know how many tests are done in each country, which would seem to be a major context variable (though the general trends all look very similar). But it appears France has started testing too late, is now at a 2,5k capacity. That's less than the UK it seems and much less than Germany. A new, faster test, has been approved for France so maybe this will start ramping up but medical experts say it's too late for a systematic approach (though one can only note it's a convenient ex post facto excuse, like masks somehow not being that useful for the general population).
And without being cynical, some egghead is probably worried that testing more and finding a lot more positive cases would freak out the population at this point, even if it would also push the fatality rate down.
I don't remember the exact number for French new cases yesterday but basically half the tests come back positive and they're probably restricted to people who already exhibit strong symptoms.