The French chess federation has suspended three top players for violating sporting ethics at a chess olympiad in Siberia last September.
The trio are alleged to have used an elaborate scheme involving text messages and computer software to help beat opponents at Khanty-Mansiysk.
Federation head Laurent Verat said it was the first case of its kind.
The players - Sebastien Feller, Cyril Marzolo and captain Arnaud Hauchard - all deny cheating at the tournament.
"There have already been suspicions of cheating in chess, even involving strong players in the past, but there has never been proof of cheating," Mr Verat told AFP news agency.
According to the French federation, while international grand master Sebastien Feller, 19, was involved in a game, Cyril Marzolo followed developments over the internet and used computer software to establish the best next move. The answer was then sent by means of a coded text message to the third member of the team, Arnaud Hauchard.
The third member would then sit himself at a particular table in the competition hall. Each table represented an agreed square on the chess board. This, according to French media reports, was the most delicate part of the operation.
The alleged strategy was discovered by French chess federation Vice President Joanna Pomian, who spotted a text message on the mobile phone of one of the three players while the French team was involved in a game.
Mr Feller and Mr Marzolo both face suspensions and say they will appeal. Mr Hauchard is facing a life ban as a chess coach and selector.
Mr Feller's lawyer Charles Morel has said that his client is prepared to fight his case. "He's convinced that he'll be cleared at the end of this process," he told French radio station Europe 1.
"For him, it's as if he hadn't worked 8 hours a day on chess for years, and hadn't reached an excellent standard and that all that was a sham."