CANNES, France – American filmmaker Michael Moore’s “Fahrenheit 9/11,” a scathing indictment of White House actions after the Sept. 11 attacks, won the top prize Saturday at the Cannes Film Festival.

“Fahrenheit 9/11” was the first documentary to win Cannes’ prestigious Palme d’Or since Jacques Cousteau’s “The Silent World” in 1956.

“What have you done? I’m completely overwhelmed by this. Merci,” Moore said after getting a standing ovation from the Cannes crowd.

The grand prize, the festival’s second-place honor, went to South Korean filmmaker Park Chan-wook’s “Old Boy,” a blood-soaked thriller about a man out for revenge after years of inexplicable imprisonment.

Moore was momentarily flabbergasted when he took the stage to accept the award, a big difference from his fiery speech against President Bush after winning the best-documentary Academy Award for 2002’s “Bowling for Columbine.”

“You have to understand, the last time I was on an awards stage, in Hollywood, all hell broke loose,” Moore said.

The best-actress award went to Maggie Cheung for her role in “Clean” as a junkie trying to straighten out her life and regain custody of her young son after her rock-star boyfriend dies of a drug overdose.

Fourteen-year-old Yagira Yuuya was named best actor for the Japanese film “Nobody Knows,” in which he plays the eldest of four sibling raised in isolation, who must take charge of the family when their mother leaves.

The directing and writing prizes went to French filmmakers. Tony Gatlif won the directing honor for “Exiles,” his road-trip about a couple on a sensual journey from France to Algeria.

Agnes Jaoui and her romantic partner, Jean-Pierre Bacri, won the screenplay award for “Look at Me,” their study in self-image centering on an overweight young woman who feels neglected by loved ones. Jaoui and Bacri also co-star.

Another jury prize went to Irma P. Hall for her role as an elderly Southern woman who foils a casino robbery in the Coen brothers’ crime comedy “The Ladykillers,” starring Tom Hanks as the heist’s ringleader.

Keren Yedaya’s “Or,” about a Tel Aviv prostitute in failing health and her teenage daughter, won the Golden Camera award for best film by a first-time director.