The Cannes film festival launched on Wednesday with quirky U.S. comedy "Moonrise Kingdom", Wes Anderson's exploration of childhood and young love centered around two 12-year-olds who fall in love and run away together.

The touching tale, set in 1965 on an island off the coast of New England, was a popular opening movie in the French Riviera resort, drawing laughs and warm applause at a press screening ahead of the official evening world premiere.

During the screening, British comedian Sacha Baron Cohen was causing chaos on the nearby Croisette promenade, where he rode a camel and adopted the character of his latest alter ego General Aladeen, an outrageously offensive North African dictator.

The publicity stunt, captured by dozens of photographers and cameramen, was typical of the kind of publicity stunts for which Cannes has become famous.

In addition to the 22 movies in the main competition lineup, hundreds more screen in lesser selections and on the huge market place, and getting the media's attention can make or break a movie's prospects.

Anderson, presenting a film for the first time in Cannes, had no such challenge, having been handed the coveted opening competition slot and boasting a cast that includes Bill Murray, Bruce Willis and Tilda Swinton.

His light-hearted, surreal picture also features two young actors marking their movie debuts -- Jared Gilman and Kara Hayward were just 12 when they auditioned for the parts of Sam and Suzy, respectively.

"I didn't know that I wanted to become an actor until I actually started working on the movie, and that's when I really began to realise that this is what I love doing," Hayward told reporters at a press conference.

In Moonrise Kingdom, Sam, an oddball and unpopular orphaned boy scout, runs away from his summer camp to meet up with Suzy, a girl with whom he has fallen in love.

Suzy's parents, played by Murray and Frances McDormand, consider her to be a problem child, and she has no qualms in leaving them to be with Sam.

The young couple set up camp, read books, become friends, and experience sexual awakening away from the troubled world of adults, but when the grown-ups eventually catch up with them their dramatic adventure does not end.

Murray, who has appeared in most of Anderson's films including "The Royal Tenenbaums" and "Rushmore", joked that the director had become his sole employer, although he did not get paid for his troubles.

"I really don't get any other work but through Wes. I just wait by the phone," he said in his trademark deadpan delivery.

"These are what we call art films. I don't know if you know what those are. They're films where you work very, very long hours for no money and...all we get is this trip to Cannes."

He also welcomed Willis into the Anderson "family".

"Bruce is a serious crazy movie star, and for him to play the part of the town cop in this one-car town was fun, it was great and it really pays off.

"He really does have the great heroic 'Die Hard' moment at the end of this silly little kids' film. It's one of the biggest laughs of any film I've ever been in."

For Willis, best known as an action hero, the chance to work on a low-budget, low-profile movie was a welcome change.

"I found it really refreshing to be directed, to be asked to perform the part in a really specific way," he told reporters.

"In a world where a lot of films where you don't rehearse and no one really talks to you about it, it was so nice to be asked to work in a certain way.

"It (the film) is about love, it's about new love and young love and love that has gotten mixed up and messed up. It's all still the same story of how everybody needs to be loved in some way," Reuters reported.