The Man Who Seeks the Truth (1940)

Original title: L'Homme qui cherche la vérité

Jean Vernet, an unselfish banker, feels fine : he has a charming mistress, Jacqueline ; a godson, Fernand, that he took in when he was a child and that he has brought up and cherished ever since ; a faithful friend, Lamblin ; and an adorable dog. But things are not so rosy as they look. Adrienne, Jean's sister, hates Jacqueline and is prepared to do everything to separate the couple. Worse, it looks as though Fernand has betrayed his godfather by sleeping with Jacqueline. To know more about those around him, Jean, a modern Volpone, decides to fake deafness.