Twenty people connected to organised crime in Marseille and Corsica face charges related to their participation in a Parisian gambling ring known as the Concorde Circle between 2006 and 2007.
Investigators paint a picture of fierce rivals vying for a jackpot worth more than seven million euros.
Through phone-tapping, investigators determined that the circle was funded through criminal activity, and have built a case around charges of money laundering, extortion, corruption and fraud.
One of the highest profile accused is Corsican nightclub owner Paul Lantieri, who gave himself up last Friday after six years on the run from the law.
He allegedly went into hiding after getting a tip from Swiss banker François Rouge, himself accused of overseeing the ring's money-laundering operations.
Investigators say Rouge got in over his head and called on former national anti-terrorist police captain Paul Barril, who is also implicated in the case.
Barril allegedly recruited a former soldier turned mercenary to resolve business deals gone bad.
The trial is expected to last four weeks, with the accused facing up to 10 years in prison if convicted on the various charges.