A new law in France makes it a crime for anyone who is not a professional journalist to film real-world violence and distribute the images on the internet.

Critics call it a clumsy effort by authorities to battle "happy slapping," the youth fad of filming violent acts — which most often they have provoked — and spreading the images on the web or between mobile phones.

The measure, tucked deep into a vast anti-crime law that took effect Wednesday, has alarmed media advocates who say it tramples on freedom of expression.

Ligue Odebi, an association that seeks to protect freedom of expression on the internet, said the measure would also hinder citizens' abilities to expose police brutality.

"This makes France the Western country that most infringes on freedom of expression and information — particularly on the internet," the group said in a statement on its website.

The measure has implications for online video sites like YouTube or France's Dailymotion.com. Authorities could ask them to identify the sources of images made available through their sites.

The new provision targets "happy slapping," a phenomenon that began in Britain and whose name belies the gravity of the attacks. Violators will be subject to up to five years in prison and nearly $100,000 US in fines.

In France, "happy slapping" appears to be rare. Police have counted about 20 cases of filmed violence or sex attacks, but acknowledge there could be countless others.

Last year, a student used a cellphone camera to film an attack by a fellow student on a teacher at a high school in the town of Porcheville. In another incident, photos were taken of a young girl who was gang-raped in Nice and the images were circulated at her school.

Some believe that shows such as MTV's Jackass, in which the regulars perform stunts involving self-inflicted pain and humiliation, are the inspiration for the acts.

French authorities have been seeking new ways to combat youth violence after a wave of rioting, car burnings and violence mostly in poor neighbourhoods on the fringes of Paris and other cities in 2005.

'Dangerous' distinction

French police first grew concerned with "happy slapping" when youths filmed during the rioting were seen using cellphones to record clashes between their friends and police.

Media advocacy group Reporters Without Borders said it understood the government's need to crack down on "happy slapping," but feared the law draws a "dangerous" distinction that would punish "regular citizens" for doing what journalists are allowed to do.

"The sections of this law supposedly dealing with 'happy slapping' in fact have a much broader scope," Reporters Without Borders said in a statement. "Posting videos online showing violence against people could now be banned, even if it were the police carrying out the violence."

Ligue Odebi noted that the approval of the law by France's Constitutional Council on Saturday fell on the 16th anniversary of the March 3, 1991, beating of motorist Rodney King by Los Angeles police officers in a scene captured on amateur video — a case that sparked a national outcry in the United States.