The film was nominated for the Academy Award for Best Animated Feature. Along with Chico and Rita, it became one of two foreign-language films nominated for Best Animated Feature in one year, an Academy first that many observers considered a surprise. The film also received a nomination for the César Award for Best Animated Film in 2011.
A black cat with red stripes has a double life. During the night, he accompanies a burglar named Nico (who calls him Mr. Cat), who makes heists to steal jewels. During the day, he lives with a small girl named Zoé (who calls him Dino). Zoé has become distant from her mother Jeanne, who works as a police superintendent, and lost her voice since the loss of her father and is looked after by a lady named Claudine.
Nico gives Dino a fish-shaped bracelet, which he passes to Zoé. At the police station Jeanne briefs her colleagues to protect the Colossus of Nairobi statue, which cost her husband his life at the hands of the notorious Victor Costa. Victor Costa intends to have another go at the statue, while it is being moved with help from his code-named accomplices, M. Bébé (Mr. Baby), M. Hulot, M. Grenouille (Mr. Frog), and M. Patate (Mr. Potato).
Back at home, Jeanne takes interest the fish-shaped bracelet and brings it to her colleague Luca. Luca deduces that the bracelet matches up to the burgled items in Rue Mouffetard. Zoé sneaks out of her house and follows Dino. She spies Victor's lot and finds Claudine is working for Victor and has been gaining insight on police movements. Zoé is spotted, but is rescued by Nico. Nico takes Zoé to hide in the zoo, but Victor's gang pick up her trail. Fortunately Zoé escapes in a boat.
Lucas finds a lead on the robberies directly to Nico's residence. When Nico returns to find Zoé at his place he is arrested by Jeanne and Lucas, presumed to have kidnapped Zoé. Jeanne leaves Zoé in Claudine's custody and goes with Lucas to find Victor. Unable to convince Jeanne and Luca of Zoé's predicament, Nico makes his escape to find Zoé. Jeanne is able to confirm that Nico's claim about Zoé is true.
Claudine has taken Zoé to Costa's house, where she is locked away. Thanks to Claudine's perfume Dino follows the scent and leads Nico to the house. Nico is able to whisk Zoé away after he cuts the power and dons on his night goggles. Victor and his gang pursue Nico and Zoé to Notre Dame, with a crane nearby. Nico falls while trying to mislead the gang, but is saved by Jeanne, who has just arrived at the scene.
As Victor catches Zoé, Jeanne with Nico and Dino come to the rescue. Nico has to save Dino when Victor pushes the cat over the edge, leaving Jeanne to confront Victor. Plucking up her courage, Jeanne saves her daughter and strikes Victor, putting him in a trance. Before Jeanne can help Victor, the gang leader swings from the crane to an imaginary statue and falls to his death into a truck below. The rest of the gang, including Claudine, are arrested and Zoé regains her voice.
Nico reforms, gives up thievery and becomes a member of the family, while Dino becomes the household pet. Nico gives to Jeanne a snow globe with the Cathedral of Notre Dame in it as a Christmas present.
Prior to the Oscar nomination, the film was little-seen in the United States, although it screened at a few children's film festivals. The New York Times called it "a gorgeous hand-drawn feature that is one of the highlights of this festival. ... Without being too frightening, it projects a sense of danger, both physical and emotional, that is more engaging than the high-pitched thrills of the domestic films."
Time Out Chicago Kids gave the film four out of five stars, describing how "this cartoon noir distills Hitchcock into 64 brisk minutes for middle-schoolers and up"; the review elaborated that the film "announces its retro visual style with a dynamic title sequence that zips across the screen, bursting with Saul Bass-influenced dynamism." It also noted that, despite the title given to the film in English-speaking countries, "its French title, Une Vie de Chat, translates as A Cat's Life."