If “The Bourne Ultimatum” is the best of the summer threes, “Rush Hour 3” is easily the worst.

Director Brett Ratner, who built a career on this buddy cop franchise, has cobbled together a lazy and formulaic action comedy that is neither thrilling nor particularly funny.

But Ratner also has the chutzpah to use the film as an anti-war statement. Jackie Chan and Chris Tucker travel to France, where a tres Parisian taxi driver (Yvan Attal) taunts them about America’s failures in Vietnam and Iraq; later, after a few adventures with these guys, the cabbie will exuberantly embrace American culture, saying he wants to know what it feels like to kill someone for no reason. The whole thing wraps up with Chan and Tucker dancing in the street to Edwin Starr’s “War.”

“Rush Hour 3” doesn’t work as social or political commentary either. Six years after “Rush Hour 2,” which grossed $329 million worldwide, it just feels as if everyone involved has been dragged back to cash in one more time.

The script from Jeff Nathanson (“Rush Hour 2”) finds Chan’s Inspector Lee and Tucker’s LAPD Detective Carter reteaming after Chinese Ambassador Han (Tzi Ma) is shot by an assassin in Los Angeles. They’re trying to determine who’s behind an international crime ring known as the Triad, and they go on the hunt for the elusive leader Shy Shen.

But first, Lee discovers the identity of the shooter after a lengthy foot chase through downtown L.A.: Conveniently, it’s none other than Kenji (Hiroyuki Sanada), who happens to have been like a brother to Lee when both were kids at a Chinese orphanage. Because Lee (like the guy playing him) is an inherently decent person, he can’t pull the trigger when the time comes.

Instead, Lee jets to Paris to find out more, with Carter at his side like an overeager puppy dog. By now these guys could do this routine half-asleep (and sometimes it feels like they are). Tucker is wide-eyed and fast-talking, Chan is stoic and serious. In every fish-out-of-water situation they find themselves in, Tucker dances and jokes his way out of it, while Chan punches and kicks.

Their investigation takes them to a kung fu studio, where the duo takes on a giant who makes Yao Ming look like Earl Boykins. (The scene also includes the funniest moment in the movie, in which Carter takes part in a rapid-fire Chinese version of “Who’s on First.”) They also visit a nightclub, hoping to find out how a mysterious performer named Genevieve (the exotic French model Noemie Lenoir) may be a crucial piece to the puzzle. It’s also a good excuse for Lenoir to parade around in a black lace bra and panty ensemble.

The big, climactic showdown takes place — where else? — at the top of the Eiffel Tower, which has some vaguely effective vertigo moments but mostly looks computer-generated. And, of course, there are the obligatory out-takes during the closing credits.

In a weird turn, Roman Polanski appears in a couple of scenes as an overly invasive French detective. And Max von Sydow co-stars as the head of the World Criminal Court, who may or may not have international harmony in mind. If Ingmar Bergman hadn’t just died, this probably would have killed him.

“Rush Hour 3,” a New Line Cinema release, is rated PG-13 for sequences of action violence, sexual content, nudity and language. Running time: 91 minutes. One and a half stars out of four.

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Motion Picture Association of America rating definitions:

G — General audiences. All ages admitted.

PG — Parental guidance suggested. Some material may not be suitable for children.

PG-13 — Special parental guidance strongly suggested for children under 13. Some material may be inappropriate for young children.

R — Restricted. Under 17 requires accompanying parent or adult guardian.

NC-17 — No one under 17 admitted.