PARIS (Reuters) - The tycoon at the center of a decades-old French legal battle that has dragged politicians and business leaders in its wake goes on trial on Monday accused of fraud.

FILE PHOTO: French businessman Bernard Tapie arrives to attend the inauguration of the Altice Campus in Paris, France, October 9, 2018. REUTERS/Philippe Wojazer/File Photo

Bernard Tapie, the larger-than-life businessman and one-time chairman of Olympique Marseille football club, is embroiled in a fight over a fraught 1993 corporate deal and the compensation he won from the state 15 years later.

The case has already been through the civil courts and prompted a 2016 trial of Christine Lagarde, now head of the International Monetary Fund but at the time finance minister, for her role in the saga. She was convicted of negligence but escaped fines or jail time.

Six people will now be tried in a criminal court, including Tapie, 76, and Stephane Richard, the chief executive of telecoms group Orange ORAN.PA, who is accused of being complicit in the disputed state payment.

Richard was Lagarde’s chief of staff in 2008.

The complex case harks back to when Credit Lyonnais bank bought Tapie’s stake in the then-struggling sportswear company Adidas 26 years ago.

The bank, which was government owned at the time, later sold its stake on for a much higher price, leading the businessman to accuse it of defrauding him.

Tapie was awarded a 403 million euro ($453 million) state-funded payout as part of a 2008 settlement approved by Lagarde. But litigation continued and he was ordered by a French court to return the funds in 2015, with the ruling confirmed by other judges in 2017.

The businessman, who is suffering from cancer, is also being tried for misusing public funds. He told France’s JDD newspaper that he was stopping any form of treatment for his illness so he could stay lucid during the trial.

“This trial is one of the most important moments of my life,” Tapie said. “What matters to me is that we establish, resoundingly, that I was not the crook.”

Richard, who is accused of hiding some aspects of the compensation deal from Lagarde, denies any wrongdoing.

“He is looking forward to being able to explain himself in public and demonstrate that the allegations against him are baseless,” his lawyer Jean-Etienne Giamarchi said.

The French government, which has a 23 percent stake in Orange, has said Richard will have to step down if he is convicted.

The trial is due to last until April 5. The accused face potential maximum prison sentences of five to seven years, and fines of up to 375,000 euros.