If ''Finding Nemo'' is an awesome Pixar superpower, The Triplets of Belleville is a charming, idiosyncratic, self-governing duchy with huge tourism potential on the other side of the animated-movie planet. Consider the Disney-resistant, anti-Joseph Campbell mythlessness of the premise: Champion, a sad-eyed little French orphan, passes his lonely childhood in the home of his patient grandmother, Mme. Souza. The boy likes watching old movies, including footage of the Belleville Triplets, an outré 1930s trio of music-hall dames who were so jazzy-hot, they shared a billing with Josephine Baker and Fred Astaire. Champion also likes his dog, Bruno. But most of all, the kid loves bicycling -- a passion Mme. Souza turns into a vocation by training her grandson for the world-famous Tour de France. (Exercise has sculpted Champion from a fat kid into a marathon gaunt athlete, save for the He-Man-size bulge of his haunches; stumpy, sturdy Granny makes a rigorous coach, clubfoot and all.)
The plot of Sylvain Chomet's unassailably French, utterly original fantasy only pedals faster from there. Champion is kidnapped midrace by menacing, black-clad mobsters (who retain their stamp-square shape with sharper angles than SpongeBob could ever sustain) and shipped across the Atlantic by boat to a looming megalopolis (called Belleville -- and suggesting architectural aspects of Quebec and Montreal as well as Manhattan while retaining the name of a run-down African and Arab neighborhood in Paris). Mme. Souza and Bruno follow, meeting up with the Triplets, who have become skinny oldies who live on a diet of frogs (oui, frogs). Rescue plans are devised... .
And all the while, Chomet and his team of animators hand-draw countless precise, funny, and sophisticated details -- part homage to the writer-director's raucous hodgepodge of artistic influences, part sly editorial and political commentary. Chomet, who lives in France and has worked in England, has said that he loves mime and character acting, Jacques Tati and Buster Keaton, the British comedy of Rowan Atkinson and the American animation of Tex Avery, and sure enough there they are, saluted in Champion's Tati-shaped posture and Keaton eyes (as well as in the minimal dialogue). The early, bubbly Triplets bop and pulse with the hotcha metabolism of Max Fleischer's Betty Boop. Champion and Bruno bond with the old-couple familiarity of Nick Park's Wallace & Gromit.
''Triplets'' looks "old-fashioned" because the animation is largely two-dimensional and the setting is superficially nostalgic; Mme. Souza's home is a picture postcard of the simpler comforts many tourists still look for in old-world Europe. In fact, Chomet's swingingest joke is in mixing up time and place -- layering a North American idea of French culture over one Frenchman's commentary on modern North American habits and tastes. As a fat Statue of Liberty presides in the harbor and obese American-style citizens bustle, the music in the air wafts with a Django Reinhardt lilt in a saga of triplets that's a singular delight.