Roman Polanski's lawyers launched a fresh appeal in a Los Angeles court Thursday, citing new evidence of judicial misconduct in his sex conviction.

They also say prosecutors have given false information to Swiss authorities in their attempts to extradite the director, who is under house arrest in Switzerland.

The filing to the California 2nd District Court of Appeal states that Swiss authorities have said they will extradite Polanski only if he will serve at least six months behind bars.

The original judge in the case intended a sentence of 90 days or less, the filing states, and prosecutors should not be suggesting his sentence would be longer if he is returned the the U.S.

The other grounds for appeal is testimony by the original prosecutor in the case, former deputy district attorney Roger Gunson, that Polanski's lawyers say was given behind closed doors.

They contend in their filing that Gunson tried to challenge the judge who was to pronounce sentence in Polanski's original 1977 prosecution but was prevented by his superiors.

This was a serious misconduct which was "hidden by the prosecution in this case for years," the emergency appeal said.

Polanski pleaded guilty to one count of unlawful sexual intercourse with a 13-year-old girl in the 1977 case, but fled the U.S. on the eve of his sentencing.

He has served 69 days in a Swiss prison and more than 100 days under house arrest at his chalet since being detained by Swiss authorities.