The Bride of Darkness (1945)

Original title: La Fiancée des ténèbres

Sylvie, a girl who believes she is cursed having seen her two lovers die in tragic circumstances, lives in the town of Carcassonne, in the South of France with her adoptive guardian, Mr. Toulzac. This one, a retired school teacher, has a passion: to discover the secret of the Cathars, a Christian sect of the Middle Ages that glorified death over life. One day Sylvie meets Roland, a pianist and composer back home in Carcassonne. A handsome and good man, he instills new hope into Sylvie's troubled mind. Unfortunately her uncle asks her then to renounce the world and to follow him down into a secret cathedral he has just found...