A film portraying the roots of Nazi violence in Germany has won the top prize at the world's biggest film festival.

The Palme d'Or was awarded to Austrian director Michael Haneke for The White Ribbon at the Cannes film festival in France on Sunday.

The White Ribbon is set in a small village in northern Germany just before World War I.

In the black-and-white film, a sinister series of crimes rocks the village and appears linked to a group of children abused by their parents.

'Fanaticism'

Haneke said the film should not be interpreted as just being about Nazi ideology, but about any form of fanaticism.

"If you are making a German film then this age is an interesting one," he said.

"If the children are 10-15 years old in 1913-1914, then they are just the right age during the Nazi regime, and that was obviously the reason to do it in this time.

"But ... you can apply it to any form of fanaticism, whether Islamic or left-wing fascism. It comes in all forms."

He also said the film had a place in modern society where television tended to provide instant answers.

"If film wants to be an art form then its duty is to treat the viewers more seriously."

Prison drama A Prophet, by French director Jacques Audiard, received the runner-up prize at the 12-day film festival.