The title should probably specify "for a presidential election". France uses an electoral college for its Sénat, it's made of regional/departmental elected people.
does it work like us presidential election tho? or are senators in France in the same "level" as electors in the US (i. e. there is no intermediate step between a voting person and elected one)?
Senators are elected by a college of locally elected people. Those locally elected people were elected, during various kinds of prior local elections, by direct universal suffrage (one adult citizen = one vote).
This doesn't really explain the difference, if any. Americans have one adult citizen = one vote. The core problem with their college is that it's not representative of the population, so the number of electors from a low population state can be the same as a high population state, effectively giving those citizens significantly more control in federal elections. It's geographical discrimination, and entirely anti-democratic. How is yours different?
= one vote in favor of the local candidate. For the Senate electoral college it gets more complicated with some places having a fixed number and others a number proportional to the population. Being fully proportional to population is not always the best solution if you want to fairly represent regions that are less populated. Is it necessarily fair for the big populated places to predominantly decide for the laws that also impact less populated place that may have different issues to handle? French Sénat system says it's better to keep a balance between population representativity and location representativity.