A former banker who testified in a French parliamentary commission tax fraud probe of ex-budget minister Jerome Cahuzac has been arrested in Switzerland, the attorney general\'s office said Saturday. Pierre Condamin-Gerbier \"was arrested on Friday, July 5, 2013. He is currently in preventive detention,\" Switzerland\'s top prosecution body told AFP in an email. It said a criminal case had been opened against him for among other things disclosing classified financial information abroad. In the land of all but sacrosanct banking secrecy, such action can be punishable with up to three years behind bars. Condamin-Gerbier was earlier this month a witness before a French parliamentary commission investigating Cahuzac, who is facing charges of tax fraud. Cahuzac resigned as budget minister in disgrace in March over an undeclared foreign bank account said to contain around 600,000 euros ($770,000). Condamin-Gerbier has told media he knew of 15 French politicians and \"big names\" with undeclared bank accounts in Switzerland and said he had handed the information over to French investigators. Also Saturday, Condamin-Gerbier\'s former employer Swiss bank Reyl and Cie said it had filed a criminal complaint against him on June 17 \"for, among other things, theft, falsifying documents and violating professional and commercial confidentiality.\" The bank, which is under investigation in France for enabling tax fraud, insisted in a statement that \"the numerous untruthful declarations given despite the bank\'s categorical denials, the falsification of an internal (bank) memo and its delivery to a French medium, has left the bank no other choice but to drop its reserve and act.\" It said it had handed all evidence in the case to the Swiss attorney general\'s office. According to news reports, Condamin-Gerbier had alleged to French investigators that his former employer had helped rich French entrepreneur Alexandre Allard, who had been living abroad, to minimise his fortune of several hundreds of millions of dollars when he brought it back to France in a bid to dodge taxes. The bank has repeatedly denied the allegations, and on Saturday reiterated that it \"has no bank account relations ... with French residents who hold or have held political duties in France.\" A Tribune de Geneve report called into question Condamin-Gerbier\'s credibility and the prevailing image of him in France as an anti-tax-evasion knight in shining armour. It pointed out that the 42-year-old Frenchman born in the central town of St. Etienne had run into trouble shortly after moving to Switzerland in 2004. After just a year working at Geneva banks, he was fired from Switzerland\'s biggest financial institution UBS after \"mistakenly\" using his company credit card 192 times in the course of eight months, to the tune of more than 40,000 Swiss francs ($42,000, 32,000 euros), the paper reported, citing a verdict against him. After that, he moved to Reyl for four years, until the bank became aware of his criminal record and showed him the door, according to the report, which said he had subsequently only worked for very short stints at two other banks and was now unemployed and drowning in debt. The paper also took issue with Condamin-Gerbier\'s testimony, pointing to several mistakes and false claims he had made to both the French parliamentary commission and to media. The former banker, who now lives in St. Prex in the southwestern Swiss canton of Vaud, had for instance told the Mediapart news website the name of a Credit Suisse banker who had handed him 1.0 million Swiss francs in cash back in the 1990s, but it turned out the man in question had never worked for Credit Suisse, it said.