PARIS (AFP) – Hollywood rebel Sean Penn, winner of the best actor Oscar for his role in "Milk," said Friday he hoped the film would soon get a showing before President Barack Obama.

"Eventually we are hoping for a White House screening," the 48-year-old told reporters ahead of the French launch of the acclaimed biopic about gay San Francisco politician Harvey Milk.

As California's Supreme Court prepares to rule on whether to annul a referendum that banned same-sex marriages last years, Penn said he expected the movie would weigh on the debate.

"I think this film will be one of the steps forward," Penn told reporters. "It will be part of the dialogue."

"But I think things are going to go forward with or without it," said Penn, who made an impassioned plea as he received his his second best-actor Oscar for opponents of gay marriage to rethink their positions.

"I was once asked to tell the difference between luxury and necessity for a human being. The right to equality for all, including homosexuals, is of course a necessity.

"That's why this right will become a reality and I think in its own way this film will be part of that."

"This train has left," Penn added, saying "the need for tolerance, equality and so on is on the move, and will go on."

In a result that has provoked nationwide protests by gay rights activists, Californians approved a proposal in November that amended the state constitution to recognise only marriages between men and women.

The passage of the measure -- known as Proposition 8 -- triggered lawsuits from activists, right groups and city officials.

The Californian court will on March 5 hear arguments in lawsuits seeking to annul the referendum, and is due to hand down a ruling within 90 days.

Penn, who was president of the jury at last year's Cannes film festival, was to hand out the best movie award at the French film awards the Cesars on Friday.

Source: AFP