Three Murderesses (1959)

Julien turns up at one of his former girlfriends' wedding; she is marrying an "old man". But the newly wed Agathe does not want to give up this hunk. She has to compete with sexy Sabine and gorgeous Helene, who has just been expelled from her sectarian school. Julien, who's also got a fiancee, behaves like a boor with the threesome. Sick and tired of this playboy's attitude, the women dream of murder. They decide to act and they steal poison from Agathe's father's pharmacy.