The Night of the Hunted
La Nuit des traquées (original)
A woman is taken to a mysterious clinic whose patients have a mental disorder in which their memories and identities are disintegrating as a result of a strange environmental accident.
Starring Brigitte Lahaie, Alain Duclos, Dominique Journet, Rachel Mhas, Bernard Papineau, Natalie Perrey, Christiane Farina, Élodie Delage, Jean Hérel, Cyril Val
Watch "The Night of the Hunted" from streaming services Amazon, BFI Player released in 1980. It's a horror and thriller movie, and has a rating of 5.5 out of 10 from Imdb which is fairly okay for this kind of movie.