Three Sinners (1950)

Noel Annequin is the black sheep of a social-climbing bourgeois family who married for love and stayed in the country while his professional brothers were improving their social position. When his beloved wife, dying of an incurable disease, begs him to end her misery, he finally agrees, but his desire to atone for his "crime" runs afoul of his heartless family, and all would be lost without his rebellious niece, played by 22-year-old Jeanne Moreau.