In the decision, the Council of State said that the budget ministry in 2009 had the authority to create a database of possible tax evaders, known as Evafisc.
The database, created in 2009 when popular anger against wealthy tax evaders was rife, is intended as a crime-fighting tool for tax authorities in their campaign to stamp out fraud and the siphoning off of funds to tax havens.
The database is fed by tips from government agencies and banking establishments, who under certain conditions are required to share information with authorities on clients holding accounts abroad.
“For the time being, we have no comment to make. We want to take the time to analyse the court’s decision,” a HSBC spokesman told AFP.
The French budget ministry said the decision “justified the means used by the state to fight tax fraud”.
Soon after the creation of Evafisc, it received information on some 79,000 customers identified from data stolen from HSBC bank in Geneva.
French authorities in January 2009 had acted on a Swiss warrant and seized HSBC customer data from former computer specialist Herve Falciani’s home in France.
The decryption of the stolen files had allowed for the identification of 127,000 accounts belonging to 79,000 people, officials said at the time.
The use by French authorities of data stolen in Geneva provoked a sharp diplomatic row, but eventually helped fuel pressure on Switzerland over tax evasion.