Polanski is under house arrest in Switzerland after his arrest last year in the March 1977 sexual assault of a 13-year-old girl in Los Angeles. The director, who pleaded guilty to unlawful sexual intercourse in 1978, says he fled after the judge said he would renege on a plea bargain. The United States is seeking extradition.
Polanski edited his latest movie, "The Ghost Writer," while under house arrest, but it is not being shown at the Festival de Cannes.
"Our role here is to celebrate the artists and the films of the people who are here in Cannes," a festival spokesman told The Hollywood Reporter. "This (petition) is for people to personally decide on, and it is not our role to speak out in this way."
U.S. actor-director Michael Douglas, who is showing the "Wall Street" sequel "Wall Street: Money Never Sleeps," passed on signing the petition.
Douglas told French Radio it would be "unfair" for him to sign a petition for "somebody who did break the law." Directors Jean-Luc Godard, Bertrand Tavernier, Oliver Assayas and actor-director Mathieu Amalric have signed the petition, The Hollywood Reporter said.