By some searching of online databases, and process of elimination, I suspect that this clip is from 1979s Enquêtes. The brunette is Cathy Stewart. If I've found the right film, then the blonde is named Samantha; she did about 5–10 films in the late 70s.
Great scene with two of my favorite French porn studs Alban Ceray and Richard Lemieuvre (the one with the beard). I think the blonde is Brigitte Lahaie.
https://xhamster.com/my/favorites/videos/5f959fa29e90f306ab3c65f7-doris-champs-dete