A French Open crackdown against online betting has attracted a lawsuit with less than two months to go before the start of the clay-court Grand Slam.

Vienna-based Bwin, an online site, is leading a lawsuit against the French Federation after claims from Paris body that wagering on matches by the public "presents a danger to the ethics of sport".

Bwin is one of the major players in the online revolution which has exploded around sports betting in recent years. The company has filed a defamation lawsuit in a Paris court.

The FFT has gone to the attack against wagering after the recent suspicious matches and the still-unresolved Nikolay Davydenko affair dating to last August.

The FFT's case is being heard in a Belgian court this week. The body has mounted a sustained campaign against online activities, sending undercover agents into the stands to keep fans at the Bercy arena from betting in real time from their stadium seats.

Some were asked to leave after placing bets on mobile phones, arbitraging the second or so between a point being one and the score being registered online in live scoring.