CANNES: Controversy gripped Cannes on Wednesday with Lars von Trier expressing “a little bit” of sympathy for Adolf Hitler and Peter Fonda calling US President Barack Obama a traitor in four-letter fashion.

The rhetorical double feature overshadowed what many expected would top the bill for uproar at the film festival, French director Xaviar Durringer's telling of French President Nicolas Sarkozy's rise to power, “The Conquest”.

At a press conference for his new film “Melancholia”, which is up for a Palme d'Or, the festival's top prize, Von Trier, a notorious provocateur, was asked about his German roots.

“I really wanted to be a Jew and then I found out that I was really a Nazi, you know, because my family was German, Hartmann, which also gave me some pleasure,” the Danish director said with a cheerful smile.

“I understand Hitler,” he added. “I think he did some wrong things, yes absolutely, but I can see him sitting in his bunker in the end.”

His star Kirsten Dunst, who is also of German descent, looked uncomfortable and murmured “oh my God, this is terrible” to co-star Charlotte Gainsbourg. But the auteur assured her: “There will come a point at the end of this”.

“I'm just saying that I think I understand the man. He's not what you would call a good guy, but, yeah, I understand much about him, and I sympathise with him a little bit, yes,” he said.

“But, come on, I'm not for the Second World War. And I'm not against Jews (but) not too much because Israel is a pain in the ass.”

"Okay, I'm a Nazi," Von Trier finally shrugged, prompting nervous laughter and leading The Hollywood Reporter, a film-industry daily, to say that he had pulled “a Mel Gibson in Cannes” referring to the actor's notorious anti-Semitic and sexist rants in recent years.

Later on Wednesday, in the festival's American Pavilion, Golden Globe winner Fonda, best known for the 1969 road movie “Easy Rider” reached for an obscenity to lash out at Obama's handling of the Gulf oil spill and aftermath.

“'You're a traitor, you allowed foreign boots on our soil telling our military, in this case the coastguard, what they can and could not do, and telling us, the citizens of the United States, what we could or could not do'.”

By “foreign boots” he meant BP, the British energy giant held responsible for the biggest oil spill in US history, which “The Big Fix” alleges is covering up the full scale of the disaster in cahoots with the US government.

Directed by Josh and Rebecca Tickell, “The Big Fix” is the only feature documentary in the official selection at Cannes this year.

Von Trier's “Melancholia” sees Dunst and Gainsbourg as sisters facing up to the end of the world caused by a collision between Earth and a bigger renegade planet. It was well-received by critics and cinema journalists.

“The Conquest”, shown out of competition and much anticipated, is the first film ever shown at Cannes, which gets much of its funding from the French government, about a serving French head of state.

It opens by saying it is “a work of fiction based on real people”, eliciting laughter from the audience, and its fairground soundtrack matches the hectic pace of Sarkozy's winning bid for Elysee in 2007. The world's biggest film festival wraps on Sunday.