Cannes, France ? Director Gus Van Sant’s “Elephant,” a disturbing film loosely based on the Columbine shootings, won top prize Sunday at the Cannes Film Festival.

Van Sant, who also won for best director, looked stunned when he accepted the Palme d’Or.

“Thank you very much, from the bottom of my heart. For years, I tried to bring one of my films to the Cannes festival,” Van Sant said. “Vive la France!”

Van Sant cast real high school students, not professional actors, in the film, and asked them to improvise their lines. The movie starts out showing an ordinary day at school, with students gossiping in the cafeteria, playing football and working in the photography lab. At the end, two students go on a shooting spree in the hallways.

Van Sant was the first American to win the Palme d’Or since Quentin Tarantino did for “Pulp Fiction” in 1994. He has never had a film compete at Cannes before, though “To Die For,” starring Nicole Kidman, showed here out of competition in 1995.

The awards capped a 12-day Cannes lineup that was widely regarded as the weakest in recent memory, and “Elephant,” though well received, was something of a surprise for the top prize.

Many critics had favored Lars von Trier’s “Dogville,” a challenging, dark, three-hour drama starring Kidman and set in Depression-era America. The movie did not win any prizes. Also overlooked was Clint Eastwood’s “Mystic River,” a crime drama about three childhood friends brought together again by a murder.

Last year, Roman Polanski’s “The Pianist” won the Palme d’Or. Polanksi went on to win an Oscar for best director, and Adrien Brody, the main character, won the best actor Oscar.

The Turkish film “Uzak,” (Distant) won the Grand Prize, or second place, this year. The slow-moving film by Nuri Bilge Ceylan is about a jobless man from the countryside who irritates his sophisticated city cousin by moving into his apartment.

The two stars of “Uzak,” Muzaffer Ozdemir and the late Mehmet Emin Toprak, shared the award for best actor. They played the two cousins — both lonely and alienated, but unable to become friends.

Toprak died in a car crash shortly after learning that the film was selected to show in Cannes; Ozdemir is an architect by profession, not an actor.

The screenwriting prize went to Denys Arcand for the critically acclaimed French-Canadian film “The Barbarian Invasions,” about a womanizing university professor who confronts death with humor and sharp intelligence. The movie, which Arcand also directed, seemed to touch the most hearts in Cannes and had many viewers wiping away tears.

Marie-Josee Croze, who plays a young drug addict recruited to supply the dying professor with heroin to ease his pain, won the award for best actress.

The Jury Prize went to “At Five in the Afternoon,” by 23-year-old directing prodigy Samira Makhmalbaf of Iran. The movie — her third at Cannes — is about a spirited young Afghan who dreams of becoming her country’s first woman president.