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?