The time is 1845 and the place is Paris, where Camille (Sidney Fox) and her scientist boyfriend Pierre (Leon Ames) are attending a carnival with two friends. The enjoy seeing the dancing girls, or the men do at any rate, and when they spot a sideshow offering a look at a real live gorilla they cannot resist entering the tent to see what's going on. They are greeted by Dr Mirakle (Bela Lugosi), another scientist who is using the show to drum up money for his research - research that most people will find outrageous...
Loosely based on the Edgar Allan Poe story (i.e. there's an ape in it), Murders in the Rue Morgue was Lugosi's first horror film after making Dracula, and arguably the one that typecast him ever after as a horror star, as from then on he would usually be playing the villain. Director Robert Florey adapted the story, and had the assistance of revered cinematographer Karl Freund (who would turn to direction himself with The Mummy that same year) to at least make his film appear as sinister as possible.
However, elsewhere the tone was uncertain. Dr Mirakle is illustrative of the dark side of evolutionary theory you see, in that he is obsessed with proving humans and gorillas can produce offspring. Exactly how he's going to do this is (thankfully) left uncertain, although we do see him performing his experiments in blood tranfusion on a "lady of the streets" as the credits coyly call her. This was one of the pre-Production Code censorship chillers, therefore they could get away with more, so there's a subtext of bestiality throughout.
Not that the film is comfortable with it, as the fun scenes of Lugosi getting up to no good are too few, with the better part of the action concentrating on the two romantic leads. This is a pity, as not only is Lugosi a fascinating and exotic creature in his best (and occasionally his worst) Hollywood films, but Ames and Fox are really awful here, and the attempts to bring humour to the table with their flirting (watch Camille gaily swing back and forth in the park as the camera follows her) do little but grate.
As for our furry friend, he's clearly a man in a gorilla suit, a costume that the filmmakers evidently don't have much faith in as they resort to closeups of a chimpanzee (not a gorilla) for authenticity, a ploy that serves to make it look even more artificial. What the film does have in its favour is an attractively gothic look, with long shadows, atmospheric sets and the blessing of that photography, a few tricks such as grotesque closeups helping keep that air of menace. What it isn't, despite the odd similarity to its source, is a decent Poe adaptation, as for the most part it's really a mad scientist movie of the kind that would run through horror and science fiction for decades to come.