Of course they can be used. The French judicial procedure will continue, Eric Woerth told reporters on the sidelines of a visit to China with Prime Minister Francois Fillon.
Despite Swiss protests, French tax authorities have been using information secured from Herve Falciani, a former HSBC computer specialist, who has admitted stealing client data from HSBC's private banking arm in Geneva.
On Monday, Paris agreed to return the data after Switzerland threatened not to ratify a tax treaty that would make it easier for French authorities to go after taxpayers who had salted away funds in Swiss bank accounts.
A Swiss finance ministry spokeswoman said on Monday the French move left a number of questions open and said these would have to be resolved between the two governments.
The essential question is what France is prepared to do with the data, she said.
A global crackdown on tax havens has forced Switzerland to relax its treasured bank secrecy regime and it promised in March it would enter new treaties that would allow it to share bank client information in some cases of tax evasion.
France and Switzerland signed one such treaty in August, which was meant to be ratified by the Swiss parliament in 2010 and Woerth said he assumed it would still be approved.
It has to be ratified. I imagine it will be. I can't imagine that the Swiss authorities will block the agreement, it's a matter of time and remaining calm, he said.
By the start of December, 1,400 of the 3,000 French taxpayers whose names appear on the list obtained from Falciani had settled their affairs with French authorities, according to a finance ministry unit that has been handling the affair.
(Reporting by Clement Guillou; Writing by James Mackenzie; Editing by Matthew Jones)