French President Nicolas Sarkozy is the subject of a 'hugely embarrassing' new film exploring why his previous wife left him on the day he was elected.

The movie called 'The Conquest' is the first ever movie about a French president to be released while they are still in office.

It portrays his rise to power in the five years before he was elected in 2007.

And French critics have said it also sheds light on one the greatest mysteries of his presidency - why Cecilia Sarkozy walked out on him on the night of the election.

The film pulls no punches as it opens with Sarkozy waking up alone at a hotel on the Champs-Elysees after celebrating his election victory.

He is then shown spending his first day as President searching in vain for the wife he married in 1996, a former top model and mother of his youngest son Louis, 13.

A scene set on the previous evening later shows him pleading with Cecilia who famously refused to vote for him, to attend the celebrations.

He tells her: 'I'm waiting for you at the Place de la Concorde. You have to come.'

She finally turns up but if seen crying by his side during the party, before she leaves alone.

The couple's marriage came under intense media scrutiny in France when Cecilia, now 52, had an affair with American millionaire Richard Attias in 2005.

Her husband responded by having a fling with a young female reporter on France's Le Figaro newspaper.

After a six-month separation, they reunited when he announced he was standing for president.

But Nicolas and Cecilia were rarely seen together during his election campaign, and after making a brief reappearance once he became president she then told a magazine she had no wish to live in the presidential Elysee Palace.

They finally divorced in October 2007 and she set up home with Attias in New York.

Sarkozy then met former supermodel Carla Bruni in December 2007 and they married after a whirlwind romance.

The new film is written by historian and screenwriter Patrick Rotman, who collected anecdotes from key witnesses to flesh out his narrative.

Producers of the film insist it depicts real events.

Sarkozy is played on screen with 'unnerving accuracy' by balding actor Denis Podalydes, who had to wear a special 'Sarkozy wig' for the role.

His wife Cecilia is played by French star Florence Pernel.

It is not known if Sarkozy has seen early rushes of the movie, but when he learned who was playing him he is said to have told aides: 'That's not right, he's got a lot less hair than me.'

France's Pure People website added: 'This is highly embarrassing for the president to be shown as his wife leaves him as soon as he is elected.

'This film is a bit of a hot potato, and quite a few potential backers pulled out.'

State broadcaster France Televisions was one company which turned down involvement in the project for fear of offending him, the website said.

The current French First Lady Ms Bruni meanwhile had lunch with the US president's wife Michelle Obama during a state visit to Washington this week.

The last time both the first ladies met, there was an uproar after an unauthorised book on Bruni said that Michelle told her life as US First Lady was 'hell'.