L'Ami de mon amie (1987)

Middle-class Parisian suburbs: Blanche and Léa, office worker and student, meet and become friends. Léa is going out with Fabien, but is thinking of leaving him. Blanche falls for Léa's handsome and witty friend Alexandre, but is tongue-tied whenever she meets him. Léa goes on holiday and Blanche, still smitten with the dashing Alexandre, begins to get to get know Fabien.