The one amazing thing that works is the taxes collection system. The French tax code is incredibly complex with hundred of special cases; yet the online system to declare revenues is perfect: super clear to use with excellent instructions, never broken (even at the end of a period where usage peaks must be insane) and with no errors.
I don't know who constructed this but it's proof that the French gvt can make good software when they really care (ie, when money's at stake).