The Midnight Witness(1953)

Jacques Montet, a successful crime story writer, has already written a hundred books and would like to call it quits now to devote himself to loftier writing. But his wife, a cold-hearted, money-minded, bossy woman won't allow. All the more as she is the one who supplies Jacques with the plots of his detective stories. When Jacques, yearning for true love, meets young, pretty Muriel, he can't stand the situation any longer. Fortunately - for him - the plot of the 101st detective story imagined by his wife is about a ... perfect crime. He simply has to follow her instructions to ... get rid of her. Everything goes according to plan until Jacques discovers a scary detail: the presence of a mysterious witness on the scene of the crime.