According to a report by French newspaper Le Parisien, evidence being used in a French investigation into tax evasion was obtained illegally after a former HSBC Private Bank employee allegedly stole the information from a branch in Geneva.

The news comes as France seeks to exert pressure on Switzerland over its banking secrecy laws, and on its own citizens to admit to holding secret accounts there.

But that task could be made more difficult following the Le Parisien report, which said a 38-year-old French-Italian computer expert had stolen client data, which eventually found their way into the hands of French investigators.

HSBC has confirmed the theft, which Le Parisien said included information about accounts held by French politicians, intelligence services, Colombian nationals and Chinese authorities.

The French daily alleged the former HSBC employer at the center of the data theft allegations has been cooperating with French authorities in ongoing money laundering and tax evasion investigations.

In August, France said it had a list of some 3,000 of its citizens suspected of using shady Swiss bank accounts to hide money with the intention of evading tax. French Budget Minister Eric Woerth said the outstanding sum was estimated at around three billion euros ($4.3 billion).

"The list comes from many sources, not only that one," Woerth told Le Parisien, implying that the HSBC accounts information was not the only source used to compile the 3,000-name list. "Nothing was paid for. This was information that was spontaneously acquired in the course of tax investigations.

"That source could be part of it, but I'm not confirming that, that's not my role ... there are several sources.

"Today this file is legally compiled. It will be used in accordance with French law," he said, briefing reporters after a cabinet meeting.

dfm/AFP/Reuters/dpa

Editor: Susan Houlton