Who are France's masked cobblestone throwers? Opinions abound

French political activists agree with the government that small groups of "troublemakers" are to blame for violence that has marred many of the protests seen nationwide over the past two months, but their identity is largely a matter of conjecture.

Highly organised, wearing masks and hurling cobblestones at security forces, they appear on the sidelines of otherwise peaceful rallies and marches.

Most agree that they actively seek violent confrontation.

On Thursday, as during previous protests against the Socialist government's hotly contested labour reforms, clashes erupted in several cities with images of burning cars and tear gas-wielding riot police battling masked protesters broadcast around the world.

Nearly 80 policemen were injured, three seriously, and more than 200 people were arrested.

- Prepared for tear gas -

Patrice Ribeiro of one of France's main police unions, Synergie Officiers, noted that the militants are well prepared for tear gas, with "their ski masks, scarves and eye drops".

"They are becoming professional," said Fabien Van Hemerlick of another police union, Alliance Police Nationale.

"They can hide their equipment ahead of time along the march route and change into their gear in public toilets or elsewhere."

Paris police chief Michel Cadot said the groups are "more and more organised and methodical... They are refining the technique of digging up cobblestones, pieces of pavement and storing them in bags, in rubbish bins and later attacking security forces when they want to."

Criminal sociologist Olivier Cahn said: "These are techniques that were developed in the 1980s in Germany that are reappearing. They want to confront the police to show that the state is losing control and to provoke images of (police) violence before the cameras."

Police sources said the "troublemakers" range in age between 15 and 30 and could be loosely described as "autonomous anarchists".

They militate for a variety of causes including opposition to public works threatening the environment, such as plans to build a regional airport near western Nantes, which has seen repeated violence in the past two months.

Cahn said the agitators were of two types, starting with the "autonomous groups dressed in black, the organised 'Black Blocs' who appear all of a sudden at the front of a march to confront the police."

The others are "groups of troublemakers made up of kids who come in from the suburbs of Paris or Lyon and take advantage of the demo to cause trouble," he said.

- Fear of 'police state' label -

The Alliance police union has faulted the government for being too afraid of being slapped with the "police state" label if troublemakers are arrested before they have a chance to act.

"It's not that easy," said a police source. "When they dig up cobblestones they are in the midst of a crowded demonstration... and to make effective arrests you need proof, videos."

But an official of another police union, Alternative Police CFDT, noted that at least the law allows police to search anyone with a face covering.

Ribeiro said the security forces could not possibly search every individual taking part in demonstrations that can attract tens of thousands of people.

Moreover, police are under orders to show restraint "especially when it's a matter of a youth demonstration... fearing a new Malik Oussekine affair," he said.

The 22-year-old Oussekine was beaten to death by police during student protests over university reform legislation in 1986.

"The troublemakers know it and are emboldened by it," Ribeiro said.

Cahn suggested the security forces were partly to blame for the violence, saying: "What is new is the way in which the state is managing these demonstrations with new, more muscular forms of maintaining order -- which provokes more confrontation".

Student leader William Martinet added that security forces in cities where protests are especially violent, such as Nantes and nearby Rennes, have used "strategies that are sometimes counter-productive".

"Rather than separating the troublemakers from the rest of the protesters, which is normally the goal, we have police who choose confrontation to disperse (peaceful) marches," Martinet, who heads France's biggest student union UNEF, told French television.