Made at a rumored cost of just over $15 million, and released in the US with the support of an advertising budget that appears to consist of $100 and a ball of string, District B13 is miles from the studio bloat of such tentpole summer movies as Mission: Impossible III and The Da Vinci Code. In place of contrived storylines and massive stars crisscrossing the globe, District B13 offers the awesome, graceful power of parkour alongside a simple story, sneaky wit and 90 minutes of thrilling, absolutely gleeful action. It might just be the best action movie of the summer.

Co-written and produced by Luc Besson and directed by long-time action cinematographer Pierre Morel, the film is set in the Paris of 2010, a city so ravaged by crime and poverty that walls have been erected around the poorest districts to keep the trouble in. As a side effect, of course, most of the help and hope is kept out. Within District B13, there is a single building untouched by the drugs and crime that dominate the rest of the walled city, and that building's unofficial mayor is Leito (David Belle). Though he keeps his building and it's occupants meticulously clean, Leito is in no way above using the same tools and tricks as the criminals he abhors: The building is guarded by heavily-armed thugs and, when we first meet Leito, he's frantically try to destroy the €1 million worth of cocaine that he stole from a K2, a thuggish District B13 gangster. Not surprisingly, K2's boss, Taha, wants payment for the coke, and he wants it now. Despite being captured in his own hideout and turned over to the police by Leito, Taha nevertheless manages to escape, taking Leito's gorgeous, ass-kicking sister (Lola, played by Dany Verissimo) with him.

And so it begins. Leito spends six months in jail, plotting his revenge and the rescue of his adored little sister (like any movie baddie worth his salt, Taha has turned her into a heroin-addicted zombie on a leash). The fact that, shortly before his release, a "clean bomb" (two million will die if it explodes, but the pollution risk is non-existent) is stolen by Taha and hidden somewhere within B13 is simply a bonus, because it means that the police sneak their best undercover agent (Damien, played by Cyril Raffaelli) into prison to meet Leito and team up with him to not only survive in B13, but also track down Taha and recover both the bomb and the girl. And, though the subplot about the bomb is surprisingly well-done -- more on that later -- what really matters to us as viewers is the action that all of this (sorted out within the film's first 15 minutes, with the aid of three impressive set-pieces) sets up.

Make no mistake: District B13 offers its fair share of gunplay and car chases and even one elaborate police action. But the movie's real magic comes from its central, mind-blowing parkour sequences. Invented and developed by Belle, the film's star, parkour is defined on parkour.net as "an art to help you pass any obstacle; to go from point A to point B using only the possibilities of the human body"; to the neophyte, it looks like a miracle. Its practitioners run up walls, leaps across impossible distances and, using only the power in their bodies, scale seemingly insurmountable obstacles. In order to make their explosive movements comprehensible, Morel photographed his stars at speeds as high as 150 frames per second which, when projected at normal speed (28 frames/second), slows their actions down enough to be seen. It's a sign of just how lightening-fast their movements are, however, that they don't really look like they're happening much slower than normal speed in the movie -- they just look a bit more graceful than usual.

With his slight build and oddly pinched, albeit handsome face, Belle is the anti-action star. Once threatened, however, he is in constant motion, never tiring or faltering as he goes over, under, or through whatever appears in his path, by they buildings, cars, or people. Raffaelli, essentially a stuntman with masterful martial arts skills (he choreographed all the stunt work in both Transporter films), matches Belle almost step for step, and when they're moving together in unison, it's something to behold. Even the most cynical of viewers would be hard-pressed not to catch his breath in awe at the sight of the pair sprinting from a speeding car and then, calmly, running up the side of a van that's blocking the street. They seem to pause for a moment as they pirouette in the air above the impact of car-on-van before coming down, untouched, behind the now-wrecked car, and sprinting back from whence they came. It's gorgeous and impossible and, best of all, real. Though some scenes were shot with wires and mattresses for insurance reasons, Belle and Raffaelli do all of their own stunts, and even the wire-aided leaps have been performed many times by Belle on his own. In our world of zillion-dollar budgets with each action movie more outrageous than the last, there's a special kind of intimacy in watching a movie that you know has few of those enhancements.

What's also special about the movie is the bomb subplot, and how what turns out to be a story of political corruption is resolved. When the good guys win, instead of tracking down the men who were willing to sacrifice two million lives for their own secret goals, and ruthlessly beating or killing them, Damien and Leito bring them to justice in a clever sting operation. Despite cop Damien's learned cynicism about laws and social rules, his partner the criminal is firmly, matter-of-factly committed to forcing everyone to abide by the same expectations, and he insists upon turning the baddies over to those who will handle them through legal channels. The sting is put together and pulled off with so much joy that it's hard to believe it's actually happening -- how could a movie already this much fun get even better and smarter in its final few minutes? But it does, and in so doing District B13 becomes the most purely enjoyable movie of the summer.