Scene: Denfert-Rochereau Metro station in Paris. A bunch of unsuspecting tourists goes up to a group of soldiers on anti-terrorist duty, resplendent in green berets and leopard-pattern camouflage uniforms, and asks for information.

One soldier yells back at the tourists in what a senior police officer describes as a strong Hungarian accent: "We are not here to give directions. We are here to kill people."

It always seemed like a risky idea. The French Foreign Legion, veterans of every colonial and post-colonial punch-up for 160 years, two-thirds of them foreigners of uncertain background, are patrolling the Parisian Metro as part of the government's anti-terror campaign. They have never been deployed in the capital before. After two weeks, the Parisian police, with whom the legionnaires are supposed to be co-operating, have had enough.

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Even the CRS, the infamous riot police, have complained that the Legion is giving law and order a bad name.

A delegation from the police unions went to the Prime Minister's office this week and, in effect, begged for the most elite, feared and unusual unit in the French army to be kept away from the capital.

The final straw seems to have been the sight of a legionnaire, once again at Denfert-Rochereau, patrolling the corridors of the Metro with an anti- tank rocket launcher strapped to his back.

This incident, also witnessed by a senior police officer, received a deadpan denial yesterday from the military command in the Ile de France. None of the 320 legionnaires taking part in the "Vigipirate" anti-terrorist campaign, it said, was equipped with a anti-tank rocket launcher.

Yvon Castel, secretary general of the federation of police unions, complained to senior officials in the Prime Minister's office that the legionnaires were harassing and roughing up Arab passengers and ignoring their standing orders not to approach and question members of the public.

"We are looking for gas canisters in the bags of biques [a racist term for North Africans]," one legionnaire proudly informed a member of the CRS, who reported the conversation to his superiors.

The Vigipirate campaign was introduced in September 1995 in response to a wave of murderous attacks on underground trains, using home-made bombs fashioned from gas canisters and nails.

The attacks are believed to be part of a campaign by French-based sympathisers with the violent anti-government campaign waged by fundamentalist Islamist groups in Algeria.

Paris is on special alert at present following tips to the French intelligence services that further attacks are planned during the celebration of Ramadan, which began two weeks ago.

The Prime Minister's office told the police unions that the legionnaires would be reminded of the limits under which they were supposed to operate.

The legionnaires were due to be relieved by other military units this week in any case. No commitment was given to keep them out of the capital in future.