The decision overturns a 2016 Swiss Federal Court ruling ordering the Swiss Federal Tax Agency (SFTA) not to comply with the French request the detail of hundreds of people with a UBS bank account after one client – a French national living in Switzerland – objected.
He appealed against the disclosure, arguing that administrative requests based on stolen data evidence are invalid.
A Swiss court ruled in his favour, adding the request “infringed the principles of good faith” implicit in the double taxation treaty between Switzerland and France.
After appealing to the Swiss Supreme Court, the SFTA won a case which ruled that the Swiss prohibition on the use of stolen data did not apply in this case.
UBS disclosure case
The case dates back to 2010, when a former marketing agent for UBS in France collected a list of 600 of the bank's customers, and sent it to the French tax authorities.
In 2013, France tax office released a list of clients who had had accounts at UBS in Switzerland that they had allegedly failed to disclose for French tax purposes.
Last year, French tax authorities asked Switzerland to name the holders of 45,161 bank accounts as part of an investigation into alleged tax fraud.
The court stated that the Franco-Swiss double taxation treaty should be interpreted strictly, and that there was no basis for refusing the international request for assistance.