MONZA, Italy — Renault has taken legal action against Nelson Piquet and his son over race-fixing claims that could lead to the French team being thrown out of Formula One.

The team said Friday that team principal Flavio Briatore has started criminal proceedings in France against former driver Nelson Piquet Jr. and his father, a three-time world champion, for making false allegations and attempting to blackmail Renault into renewing Piquet Jr.'s contract for the 2009 season.

Renault has been summoned to a hearing by governing body FIA on Sept. 21 to answer claims that Piquet Jr. was asked to crash at last year's Singapore Grand Prix to improve teammate Fernando Alonso's chances of victory. The Spanish driver went on to win the race.

"Renault F1 Team and its managing director Flavio Briatore wish to state that they have commenced criminal proceedings against Nelson Piquet Junior and Nelson Piquet Senior in France concerning the making of false allegations and a related attempt to blackmail the team into allowing Mr. Piquet Jr. to drive for the remainder of the 2009 season," Renault said in a statement. "The matter will also be referred to the Police in (Britain)."

Piquet Jr.'s contract for 2009 had still not been renewed by the time of the Singapore GP. Briatore fired the Brazilian driver after the Hungarian Grand Prix on July 26 after 1½ seasons with the French team.

Piquet is believed to have informed FIA on the allegations, which the governing body is investigating.

FIA confirmed Friday that Piquet Jr. had been promised immunity from prosecution in return for his testimony. McLaren drivers Lewis Hamilton and Alonso were given immunity in 2007 to testify during a spying scandal over documents leaked from Ferrari to the British team.

Renault launched the legal action a day after a supposed statement Piquet Jr. gave the FIA was leaked to various F1 Web sites. The FIA refused to verify the verity of the statement again on Friday.

The Formula One Teams Association expressed "concern" at the leaking of the document.

"All parties to the dispute should have the right to a fair hearing carried out in private and not in the public arena, which is producing adverse publicity damaging to the corporate image and credibility of Formula One," FOTA said in a statement.

Piquet Jr.'s crash after 14 laps at F1's inaugural night race brought out the safety car shortly after Alonso had pitted. The two-time world champion was then able to position himself for victory by moving up the grid behind the safety car, which lapped the track seven times before coming into the pit lane.

Alonso denies having any knowledge of the alleged plans.