There are countless reviews of this seminal film to be read on the internet, so I shall direct my focus away from the aspects with which most of them deal.
Consider, for example the backdrops. Have you noticed how detailed and intricate they are? Every cobblestone in a street is seen, every crease on a bedcover, every scratch on a door handle - every shot is crammed with detail. I cannot recall seeing a blank wall or a plain open space.
This richness of visual detail is usually missing in Hitchcock films. I also find a richer dialogue than Hitchcock at this period ever provided. Richer too is the cast of eccentrics, drunkards, neighbours, and bit players. The drunkard who attempts to secrete himself in the back of the van containing the body in the basket, once seen, is never forgotten.
Writers Pierre Boileau and Thomas Narcejac wrote the novel and the film rights were obtained by Clouzot only hours before Hitchcock's bid was received. Never mind if Simone Signoret usually has a cigarette protruding from her mouth in the early scenes, never mind that she and Vera Clouzot are made to totter around on the absurdly high-heeled shoes women wore in the mid 1950s, this is a film that will look good and captivate audiences forever.