PARIS - The Paris underground rail service has pressed a one million euro ($1.82 million) damages claim against 62 people accused of defacing its billboard adverts in a case which has become a cause celebre among France's far-left.

The suit follows four incidents last year in which hundreds of activists used spraycans, markers and paint to daub messages such as "Advertising Kills" on thousands of posters in metro stations.

France's large anti-capitalist movement has rushed to their support and the case has attracted newspaper headlines in a country where mistrust of multinational corporations and globalisation runs high.

Much of the inspiration for the graffiti raids comes from books such as Canadian author Naomi Klein's bestseller "No Logo", which argues that multinationals are bombarding consumers with increasingly intrusive advertising to ensure they notice their brand.

"The metro is first and foremost a public service whose function is to transport people," defence lawyer Alexandre Faro told a four-hour hearing in a Paris court jammed with the accused, mostly in their 20s, and their supporters.

"Yet, as a passenger you are a sitting-duck target. This is vulgar, disgusting advertising," he told the court, holding up examples of billboard advertising that used female nudity and contained sexual innuendo.

The so-called metro warriors, who include seasoned anti-capitalist campaigners, feminists and a smattering of novice activists, responded to calls for action sent out by internet websites.

Only five of the 62 accused admitted involvement in raids from October to December. Lawyers for most of the remainder said that police who carried out arrests inside metro stations had not provided enough evidence against them.

The verdict is due on April 28.

Jacques-Henri Cohn, lawyer for Paris metro operator RATP, said it was inconceivable that just five people could between them have defaced 2440 posters in the four raids. He dismissed defence arguments about the nature of the ads as irrelevant.

"We are not against the (anti-advertising) movement itself. But we object to them feeling they can deface the billboards," he said, adding that the damages claim reflected the estimated cost of replacing damaged posters and reimbursing advertisers.

The accused have won support from a number of left-wing groups, including ecologist Green Party members of the Paris city council. The Paris Greens have asked RATP to drop the case against them and cut down on advertising in its stations.

RATP has argued that advertising is in the public interest because it provides the state-owned operator with 65 million euros a year -- enough for 20 new metro carriages or 300 buses.