For me i think that in your example:
- “Paul Mauriat & His Orchestra” should be a single group artist related to main artist “Paul Mauriat”.
- “Le Grand Orchestre de Paul Mauriat” can be an aliases of “Paul Mauriat & His Orchestra” or a separated group depending of the purpose of this name.
I think it’s not different from any group of music. “Queen” might have been called “Freddie Mercury and his band”, for me this is the same.
Nevertheless, I just think that musicbrainz should show by default in the discography of an artist all entries related to the groups he is marked as members.