Dublin-based Orbiscom Ltd, which supplies clients such as Visa, PayPal, Citibank, Wells Fargo and MBNA with security systems to eliminate internet card theft and "skimming", will defend a 21m claim in Toulouse Court of Appeal next month. A date for the hearing is to be set by the court on 13 September.

Orbiscom's chairman, Paschal Taggart, said that the plaintiff company, Syrdrec SA, located in the small Mid-Pyrenees town of Masseube in south-west France, "has no chance at all". He described the law suit as "their last throw of the dice to embarrass us", having lost an initial court hearing in France two years ago.

The potential damage to Orbiscom can be gauged by the sheer size of the international credit card market and the growing rate of internet transactions. PayPal, eBay's online subsidiary, took in 322m for the first quarter of this year, an increase of 31%. Visa, another of Orbiscom's clients, has over one billion cards in circulation.

Syrdrec is claiming that it developed an anti-fraud system for electronic payments in 1991 in conjunction with another company, EDS-GFI. The design was registered as Tictel but it was never commercially produced "because of conflicting market conditions". In 2002, Syrdrec discovered that Visa cards in France were using a system called e-Carte Bleu which, Syrdrec claims, is an infringement of its patent.

"This case will go all the way, " predicted Emile Schmitz of Syrdrec, who has sent a press release flagging the upcoming court appeal to numerous American and European sites.

Orbiscom was founded in 1998 by Dubliners Graham O'Donnell and Ian Flitcroft. Their card security design was registered with the World Intellectual Property Organisation on 25 March 1999.

The company's international head office is in Blackrock, Co Dublin. Orbiscom was valued at 18m in 2000 by Goodbody stockbrokers but it underwent a radical restructuring after clocking up accumulated losses of 24.5m in 2003. Its backers are HG Capital, GLC Partners, some private clients of Goodbodys and AIB. Other shareholders include Taggart and John Nagle, founder of Alphyra, a technology company.

Taggart said the company and its subsidiaries will be fully represented in court by their French lawyers on 13 September.

"They claimed we were violating their patent but we went to court a couple of years ago and proved our patents preceded their claims, " he said. "This is a frivolous last gasp for publicity."