Moore's film, called "Fahrenheit 9/11," claims that Bush stole the U.S. presidential elections of 2000 and that he has close business ties with relatives of Al-Qaeda leader Osama bin Laden. The film also is highly critical of the Bush administration for its invasion of Iraq and other policies since the terrorist attacks of 11 September 2001.
Film director Quentin Tarantino, who was the president of this year's Cannes jury, announced the prestigious award late on 22 May.
"I have a sneaking suspicion, thanks to what [the Cannes Film Festival jurists] have done here and the response from everyone at this festival, you will ensure that the American people will see this movie." -- Michael Moore
Moore says Tarantino told him privately that the politics of "Fahrenheit 9/11" had nothing to do with the jury's decision. Moore says Tarantino whispered to him on stage that he was given the award because he had "made a great film."
The Walt Disney company, which provided funds to produce "Fahrenheit 9/11," recently told its Miramax unit not to distribute the politically charged documentary during a presidential election year in the United States. Disney officials have said that the partisan nature of the film could offend some viewers.
Moore has publicly accused Disney of censorship, alleging that the company is afraid of losing tax breaks in the state of Florida, where one of its main theme parks is located and where Jeb Bush, the brother of the U.S. president, is governor. Moore referred to the distribution controversy in his acceptance speech for the Golden Palm.
"It's been a rough few weeks because we've lost our American distributor. But I'm happy to announce that we have a distributor now in Albania. So now, every country in the world can see this film except one," Moore said.
But Moore said he hopes that winning the prestigious Golden Palm will help to get "Fahrenheit 9/11" distributed widely in the United States during the summer so that American voters have a chance to see the film and consider his criticisms of the Bush administration before the November elections.
"I have a sneaking suspicion, thanks to what [the Cannes Film Festival jurists] have done here and the response from everyone at this festival, you will ensure that the American people will see this movie. You've put a huge light on this. Many people want the truth to be put away -- to be put in the closet. And you've taken it out of the closet by this act," Moore said.
In Washington, White House spokeswoman Suzy DeFrancis attached little significance to the decision by the Cannes jury to honor the film. Speaking in a telephone interview with the French news agency AFP, DeFrancis said the United States is a great country because it is "a free country where everyone has the right to say what they want." DeFrancis said the Bush administration would not make any further comment about the film.
Strong anti-Bush sentiments were on display during the 22 May awards ceremony in Cannes. Belgian filmmaker Jonas Giernaert urged Americans to vote against Bush in November. British actor Tim Roth later told the audience before presenting an award that Giernaert was "extraordinarily brave," and repeated that Americans should not reelect Bush.