That Murders in the Rue Morgue ended up being set in Paris around 1845 was partially the result of his [Robert Florey] familiarity with the time period, for he had been one of King Vidor’s helpers on MGM’s lavish production La Bohème (1926). “The costumes”, said Florey, “worn by the stars, bit players and extras had been kept at the Western Costume Company and being aware of it I had adapted the Poe story to the same period, the only wardrobe expense of Universal being the cost of the rental”. Florey must have been informed that the 1845 setting was approved, and after he had some of his budget restored he returned to the project. But return to what? According to “Variety”, “a corporal’s guard of writers” had worked on the script, which had been violently gyrating among the various studio factions throughout the summer, and it finally seemed ready. The script now adhered to the dramatic strategy and many of the plot devices of Frankenstein, just as a year later The Mummy would draw upon several story aspects of the Dracula film. Rue Morgue had Dr. Mirakle instead of Dr. Frankenstein, an ape instead of a monster, the Black One as an assistant instead of Fritz, and a chase over the rooftops instead of in the mountains. (…) The writers of Murders in the Rue Morgue, and certainly its director, knew about The Cabinet of Dr. Caligari (1919) – in fact, the German silent film was screened at the studio in June 1931 – and its look as well as some of its plot elements were appropriated: the exhibition of the creature by the doctor at a carnival, the doctor’s lack of regard for human life, and the creature’s violent entry into the girl’s bedroom. Even more influential was the film’s expressionism in lighting and set design. At other times the movie reflects Karl Freund’s skill at cinematography, with low-key lighting, camera movement, and atmospheric, misty shots.

Arthur Lenning, The Immortal Count: The Life and Films of Bela Lugosi, University of Kentucky, Lexington 2003