Magistrates accuse Sarkozy and his lawyer, Thierry Herzog, of having proposed a prestigious job in Monaco to former magistrate Gilbert Azibert in exchange for tip-offs on an inquiry into allegations that Sarkozy had exploited the mental frailty of late L'Oreal heiress Liliane Bettencourt to enjoy donations in cash to finance his 2007 presidential campaign, Xinhua news agency reported on Monday.

Sarkozy, 65, led France from 2007 to 2012. He is the first ex-president in modern France to appear in the dock. He denied all wrongdoing.

"I have never committed the slightest act of corruption," he told magistrates.

"I want to be cleansed of this infamy, not just by procedure ... because I want the truth of the facts and law," he was quoted as saying by local media.

Herzog and Azibert also face trial on charges of corruption, trading in influence and concealment of breach of professional secrecy.

If the accusations are proven, Sarkozy risks a 10-year prison term and a one million euro fine.