CANNES, France (Reuters) - With World Cup fever building, French soccer star Zinedine Zidane appears on the big screen at the Cannes film festival this year in an offbeat documentary that took many viewers by surprise.

"Zidane: A 21st Century Portrait" is impressionistic and experimental, far removed from the standard documentary treatment of famous people.

The midfielder is filmed in real time from 17 different cameras during a home game in April last year between his club Real Madrid and Villarreal, using closeups of his face, ankles, hands, legs and torso or panning out to show the whole stadium.

Images move in and out of focus and the sound is at times a deafening roar and at others turned down to silence. Electronic music builds tension and the soundtrack also includes a recording of a soccer game on a school playground.

Unlike television coverage of the sport, there is little in the way of context, only complete focus on one player who drifts in and out of the game.

Zidane, now 33 and due to retire after the World Cup, displays his usual brilliant close touch and vision, at one point ghosting past three defenders to loft an exquisite cross which a teammate heads into goal.

But the film also appears to be making the point that soccer is just a game, of little wider significance, and involves men running up and down a field of grass and around in circles.

At halftime the film, directed by Scottish-born artist Douglas Gordon and French director Philippe Parreno, cuts to news footage of a suicide bomb in Iraq. One young man at the scene of the carnage wears the shirt of Zinedine Zidane.

ZIDANE'S REFLECTIONS

Zidane does provide occasional quotes through subtitles written in French on the screen, in which he ruminates on the game and life.

"Sometimes when you arrive at a stadium you feel everything has been decided," he says in the subtitles. "The script has already been written."

Zidane was a World Cup winner with France in 1998 and became the world's most expensive footballer when Spanish club Real signed him for $66 million from Italy's Juventus in 2001.

Production notes show Zidane initially was not interested in the project, but the production team won him over. He was not in Cannes to promote the movie due to World Cup training ahead of the tournament which kicks off in Germany next month.

Critics warned audiences expecting a traditional expose of Zidane that they would be disappointed.

"The picture offers an audiovisual portrait of a 21st century icon in a new millennium way," wrote the Hollywood trade magazine Variety, which predicted mixed reaction among film goers to the documentary.

The Hollywood Reporter was more scathing.

"See a bald man in shorts, past his prime, covered in sweat and looking puzzled," it wrote in its review.

The end of the film packs a punch as Zidane is sent off for his involvement in a fracas near the end of the game.

"Magic is sometimes very close to nothing at all ... Nothing at all," comments Zidane, before concluding: "When I retire I'll miss the green of the field."