That Most Important Thing: Love (1975)

Servais Mont, a photographer, meets Nadine Chevalier who earns her money starring in cheap soft-core movies. Trying to help her, he borrows the money from the loan sharks to finance the theatrical production of 'Richard III' and gives Nadine a part. Nadine is torn apart between Servais, for whom she is falling in love, and her husband Jacques, to whom she has moral obligations.