For what it's worth, unlike in most other countries, excess mortality in France in 2020 roughly tallied with recorded covid deaths, suggesting that the system there is relatively more accurate than elsewhere, although obviously not perfect.
If you are a close contact of a confirmed case, you are instructed to take two tests regardless of whether you have symptoms. That must catch a large number of asymptomatic cases that wouldn't be recorded in the UK. It's also very easy now to get a test for any reason.
Finally, hospitalisation rates relative to cases have consistently been higher than in the UK, suggesting that maybe serious cases are treated sooner.
Care homes, on the other hand, were a complete disaster during the first wave.