ZURICH (Reuters) - A Swiss court has ruled that bank UBS
The Federal Administrative Court found that requests for information must state why authorities believed taxpayers did not fulfil their obligations.
"Keeping an account in Switzerland is not enough," it said in a summary of its ruling released late on Tuesday.
France has the right to appeal to Switzerland's highest court.
French tax authorities had asked their Swiss counterparts for help in identifying the owners of several thousand UBS accounts in Switzerland believed to be held by French taxpayers. UBS and account owners had fought the request.
France and other European Union countries have launched a campaign to encourage taxpayers to come clean on previously undeclared assets held abroad, and have clamped down on aggressive tax optimisation techniques by multinational companies.
Switzerland, whose strict banking secrecy had long made it a haven for offshore wealth, has now begun the automatic exchange of bank data with other countries.
UBS still faces a trial in France over charges of aggravated tax fraud and money laundering as well as illegally offering related services, a judicial source has said. The bank has disputed the allegations of wrongdoing.
UBS settled a tax case with German authorities in 2014 for around 300 million euros (£267.2 million).
(Reporting by Michael Shields; Editing by Susan Fenton)