Quai des Orfèvres, a Parisian krimi that came out in the year of my birth. Back then Parisians still spoke at 400 syllables/minute, about four times faster than the English - following it took a bit of an effort. A grimy little story revolving around variety theatre, a rising star, a lascivious ancient and a jealous husband, with a phlegmatic cop slowly picking them all apart. Some bloody wonderful singing, but no decent views of Paris, which we were hoping for.
ETA: The name of Peter Seller's Inspector Clouseau could well be a nod to Henri-Georges Clouzot, who screen-wrote, produced & directed this film. And the theatre used in the film looks very like the favourite theatre of Louis Jouvet, the male lead. It's now named for him.