The City of Lost Children

Who has stolen the child's dream?
The mad genius Krank in his evil scheme.
To what vicious depths will he not descend?
Will the tale turn to tragedy...
or have a happy end?

A French science fiction film following a circus strongman One (played by Ron Perlman) and a streetwise orphan Miette in their attempts to save One's adopted little brother from Krank, a mad scientist who steals dreams. It opened at the 1995 Cannes Film Festival, and was directed by Jean-Pierre Jeunet and Marc Caro, who also directed the similarly dark Delicatessen.

Tropes used in The City of Lost Children include:

Adorable Evil Minions: The five cloned brothers.
Adventure Narrator Syndrome: Miette says, "I can't do that!" if you keep clicking in the wrong places in the video game adaptation. And it could happen a lot too.
Anti-Villain: Krank suffers everything his victims do in his failed experiments, is pathetically incapable of understanding why even his kindest acts only frighten the children, is shown to suffer horribly from Uncle Irvin's verbal abuse, and is hinted to be the result of some other Big Bad's hideous and twisted experiment himself. Even at his worst, his condition is so pitiable, it's heartbreaking.
Bad Dreams
Big Brother Instinct: One has this, first for Denree and then for Miette.
Big Eater: Denree. Played for cuteness, although it's not terribly endearing to watch his open-mouthed munching.
The Big Guy: One, who is a circus strongman.
Brain In a Jar: Uncle Irvin.
City with No Name
Cloning Blues: Five cloned brothers serve Krank, and they're not sure which is the original. It's none of them: it's the Diver.
Conspicuous CGI: The flea sequences and the roving nightmare message. Considering that the film was made in 1995 though, the CGI was really isn't too bad for its era.
Crapsack World: The city is depicted as ugly and polluted and bearing an extremely grim atmosphere, the police force is incompetent enough so that children are constantly kidnapped by Krank's associates, the Cyclops organization practically terrorizes the entire city, and no one seems to have guts to stop them and citizens are occasionally mugged by the kids under the control of the Octopus.
Disaster Dominoes: An elaborate series of chained events ends up saving One and Miette from the Octopus.
Dubtitle: On the official Region 1 DVD, not only are the English subtitles almost verbatim to the dub, but the French subtitles are back-translated from the English dub.
Dumb Muscle: It's strongly suggested that One is developmentally challenged.
Emotionless Girl: Miette starts off as this.
The Fagin: The Octopus's side job.
Faux Fluency: Ron Perlman was the only American in the film and memorized all his lines, since he did not speak French. He did an excellent job from all accounts.
Gentle Giant: One.
Grandfather Paradox: Miette, in Krank's dream, turns him into a child, so as a child, he is put into the dream machine to be put into his own dream, creating a loopback paradox that kills him.
Hoist by His Own Petard: Krank, in the end.
Huge Guy, Tiny Girl: One and Miette.
Hulk Speak: One.
Instrument of Murder: The music box.
Intergenerational Friendship: One and Miette.
Lady in Red/Little Dead Riding Hood: Miette
Licensed Game: For the PlayStation and PC. And it was even sold in the US despite this film's extremely niche appeal.
Mad Scientist: Krank and his creator, the Diver.
A Nazi by Any Other Name: The Cyclops leader has more than a touch of Hitler in his oration. His appearance is also more than a little reminiscent of Chairman Mao.
Not Even Bothering with the Accent: Miette speaks with a British Accents in the video game adaptation despite the fact that her character is French in the original film.
Psychotic Love Triangle: The professor created Martha to be a wife. By the time Krank turns against him, she is loyal to his other creation (making this a case of an attempted Murder the Hypotenuse) which may have contributed to their eventual betrayal. Once their maker is gone, they are together, making this possibly the strangest Love Triangle to appear on film.
Single-Minded Twins: The Octopus.
Skyward Scream: One does this when he thinks Miette has drowned.
Steampunk: Well... Gaslamp Fantasy, really.
Suicide Attack: The Diver blows up the lab with a suicide bombing at the end.
Twin Telepathy: The Octopus, to the point of being practically a Hive Mind.
Water Is Air: The mad scientist, as a diver with amnesia, lives permanently at the bottom of the sea near the harbor, collecting flotsam, jetsam and derelict.
Wise Beyond Their Years: Miette, who considers One to be her little brother.