At 17 minutes when they get out of the Alfa Romeo, Claude parks behind a 1980s Mazda 323.
Fernande and Sidonie ride in a Mercedes. It is supposedly year 1970, but the car is a post 1973 face lift model with grooved rear lights and wider grille.
She says that they call them friends instead of clients, then calls them clients twice.
Claude's daughter Anne's age doesn't track with the script. The movie says Claude was born in 1923 and then her voice over says she got pregnant at age 17 and had a daughter, which would put the daughter's birth at 1940 or 1941. The film is set in the late 1960s and the actress playing the daughter appears to be teenager when she should have been in her late 20s.