Maigret Has Scruples

Xavier Marton, the head of the toy department at the Grands Magasins du Louvre, a model train specialist, visits M to say that he thinks he wife wants to poison him, but leaves while M is out of the room. Later in the day the man's wife, Gisele Marton, also visits M, to tell her side of the story, which is that her husband is having delusions. Marton comes the next day, and agrees to have another examination with a psychiatrist. But he warns M that if she poisons him, he'll shoot her before he dies. Meanwhile, M has had both of them investigated, and finds that Gisele's sister, Jenny, is living with them, and that Marton is apparently enamored of her. Gisele, on the other hand, is apparently the lover of her employer, M. Harris. M has the house watched during the night, and by morning Marton is dead, accidentally poisoned by Jenny, when Gisele switched her cup of tea with her husband's. He had poisoned his own, with enough to make him sick, but not to kill him. Jenny thought he hadn't the nerve, so she added the poison to kill her sister.