French search engine 1plusV said it is suing Google for 295 million euros ($418 million), alleging the US company used its dominance to thwart rivals.

The French company is one of four, including Microsoft Corp  , that have accused Google of abusing its dominant position by demoting rival sites in search results and giving preference to its own services. The allegation has triggered an investigation by the European Commission.

The US Federal Trade Commission last week also opened a formal probe into Google's market practices, raising the spectre of a protracted regulatory battle on both sides of the Atlantic for Google -- similar to Microsoft's earlier fights with the authorities.

1plusV, which runs the Ejustice.fr legal website and search engine, says that Google prevented it from developing specialised "vertical" search engines and crippled its ability to generate business and advertising and the claim is for lost and future profits.

"Between 2007 and 2010, no less than 30 vertical search engines created by 1plusV were black-listed, some of which showed significant business potential," it said.

Google said it had been notified of the claim.

"We have only just received the complaint, so we can't comment in detail yet," Google spokesman Al Verney said.

"We always try to do what's best for our users. It's the key principle that drives our company and we look forward to explaining this."

A lawyer for 1plusV said the claim will be filed with the Paris commercial court on Tuesday or Wednesday.

The damages claim could be just the first of a series, said Thomas Vinje, a partner at law firm Clifford Chance, who led a coalition that won EU fines against Microsoft.

"I would not be surprised if it encourages others to do the same. In general, it is becoming easier to obtain damages in competition cases across Europe than in the past," he said.

British price comparison site Foundem, one of the complainants against Google, could not be immediately reached for comment. Microsoft, which owns the fourth complainant -- German price comparison site Ciao -- could also not immediately be reached for comment.

1plusV accused Google of suffocating rivals through its policy of tying its advertising service Adsense to its own search engine.

Google's Adsense allows advertisers to buy keywords which when typed in as a search query produce a commercial link alongside the search results. Thus rival search engines wanting to access vital clients and revenue were forced to adopt Google technology.

The European Commission is now investigating the complaints. The European Union executive, with the power to fine companies up to 10 per cent of their global turnover for breaching EU rules has hit Microsoft with fines totalling more than 1 billion euros. – Reuters