Sharon Stone, Sofia Coppola and Samuel L Jackson were among the guests at an Aids charity ball in Cannes.
Sharon Stone hosted the auction
The annual event, which coincides with Cannes Film Festival, aims to raise money for the American Federation for Aids Research (Amfar).
"There are now 14 million people with the illness. We can't stop until we have a vaccine and I do believe that we can find those answers," said Stone.
The actress said they had already raised $2m (£1.06m) in tickets sales.
Stone and former Miramax boss, Harvey Weinstein, were in charge of the evening's auction.
Actor Robin Williams joked: "I'd like to bid for the car but I might have to check whether that's OK at home first."
The charity, which has Dame Elizabeth Taylor as its president, has invested nearly $250m (£133m) in its Aids prevention, research and treatment programme since 1985.
Actress Faye Dunaway and actor Gael Garcia Bernal also attended the benefit.
Sir Elton John, a big supporter of Aids charities, pulled out because of sore throat but his partner David Furnish was there to support the event.
Furnish said: "The problem is getting worse not better and the fight against Aids is getting harder and harder because of politics and religion.
"Awareness is particularly important, I have a lot of friends in the room and I will encourage them to dig deep into their pocket. The tiniest bit of money can make a huge difference."