There are few things that a politician fears more than ridicule but this is especially so in France, where snigger-angst is etched in the genes.

Put yourself in the thin skin and elevator shoes of President Nicolas Sarkozy as he contemplates an upcoming movie about his controversial rise to power.

La Conquete (The Conquest), to be shown at the Cannes Film Festival which opens tomorrow, is being promoted in the press as an unprecedented mix of eye-popping skullduggery and ego-popping comedy.

Drawing on what its makers say are real-life events and verbatim conversations, La Conquete vows to expose the ruthlessness, paranoia, foul language and raw insults that lie behind politicians' public smile and suave statements.

The movie's source material is indeed compelling.

Short on height but big on ambition, bossy but funny in equal measure, Sarkozy is an outsider who for five years fought his way to the top job after shouldering aside the old guard.

On the way, Sarkozy fell out with his predecessor and one-time mentor Jacques Chirac, as he faced traps and cabals set by Chirac's lieutenants.

He fought viciously with former Foreign Minister Dominique de Villepin, whom he suspected of framing him in a case of financial sleaze.

Sarkozy famously vowed to hang the sleek-haired diplomat "on a meathook".

Just as he set his hands on the glittering prize in May 2007, Sarkozy was laid low by wife Cecilia, around whom his entire life revolved.

Cecilia, who had plotted his career down to the finest detail, left the newly minted President for another man.

It is the first time that the French cinema has made a feature-length movie about a national leader still in office, a format blazed by the British film The Queen and W, Oliver Stone's biopic about George W. Bush.

La Conquete will be released on May 18, little more than a year before the next presidential elections and at a time when Sarkozy's opinion-poll standing is plumbing the depths.

But director Xavier Durringer denies that this will be a hatchet job or an attempt to sway the vote. He sees it as the portrayal of a complex character, caught in the dilemma of ambition and love.

"It's the story of a man who conquers everything and loses his wife," said scriptwriter Patrick Rotman.

Rotman, a historian by training, said he spent months reading books about Sarkozy and interviewed Cecilia at length to help portray scenes which, he claimed, are as accurate as is possible in a motion picture.

The film's poster, devised by a British ad agency, shows the diminutive Sarkozy perched on a stool that is cranked up to such a height that his head is cut off and his feet cannot touch the ground.

The trailer shows Chirac's killer streak beneath an avuncular exterior.

"I should have crushed him," Chirac sighs. "I should have done it with my left foot, it brings good luck."

"Many people are going to be surprised by the violence and cruelty of the language," said Rotman.

"It's because in politics, you kill with words. Every journalist who hangs around politicians knows that when the camera and the microphone are off, they all curse like troopers, especially Chirac and Villepin. Sarkozy's thing is to fly into towering rages with his entourage."

Sarkozy is portrayed by Denis Podalydes, whose last big gig was as Richard II at the Avignon arts festival last year.

"What interested me about the role was the challenge of not showing Sarkozy in the image which he offers to the public but instead to seek out his moments of abandonment, of sadness, to find a rhythm of behaviour by using simple moments," Podalydes said in an interview with the newspaper Nice Matin.

Meanwhile Sarkozy's current wife, supermodel-turned-singer Carla Bruni-Sarkozy, plays a cameo role as a museum guide in a Woody Allen film, Midnight in Paris, which has been chosen for the festival opening.

The film has a roster of stars, including Marion (La Mome) Cotillard, in a screwball comedy with Paris as its romantic backdrop.

The New York Times describes Midnight in Paris as a stinker that should never have left the drawing board. "This germ of an idea calls for an antibiotic," it said.