It's a common mistake to judge the entire west from an US perspective. But the UK is not very far from the 2 parties system either.

Arguably the UK is a "2-party-but" system. The main parties are limited in their policies towards Scotland because of how much influence the SNP has, and we've seen what UKIP managed to do while barely ever winning seats. There's enough of a threat from smaller parties to keep the big ones somewhat cooperative, or at least take a wider range of views into account.

France is closer and closer from a 2 parties system

Bullshit, look at any election from the past 5 years and there are at least 5 mainstream parties - PS, LR, RN, LREM, EELV. PS are in a bit of a crisis but still do decently in local and European elections.

France is currently a 1 party system.

France is always a 1 party system in regards to who is in direct central power, since parliamentary elections are just after presidential ones, to send the winning president a parliament they can work with. In almost all cases the ( slim) majority the ruling party has falls apart over the course of their term.

And that's why there's an indirectly elected upper chamber ( Senate), to avoid a populist wave changing too much.