The bank was convicted of illegally helping French clients to hide billions of euros from French tax authorities.

The trial opened last autumn after seven years of investigations, launched when several former employees came forward with claims of unlawful conduct. 

The move came as authorities across Europe cracked down on tax evasion and dubious banking practices in the wake of the global financial crisis which erupted in 2007.

The pressure eventually forced Switzerland to effectively end its tradition of ironclad bank secrecy, by joining more than 90 countries which agreed to automatically share more client account information among each other.

In the UBS case, French authorities determined that more than €10 billion had been kept from the eyes of tax officials between 2004 and 2012.

The National Financial Prosecutor's office had urged a €3.7-billion ($4.2 billion) fine, the largest ever sought in France, saying the bank and its directors “were perfectly aware that they were breaking French law” by unlawfully soliciting clients and helping them evade French taxes.

They had also sought a €15 million fine for UBS's French subsidiary, and fines of up to €500,000 for six top executives, including Raoul Weil, the former third-in-command at UBS, and Patrick de Fayet, formerly the second-ranking executive for its French operations.

In addition, lawyers for the French state, which is a plaintiff in the case, asked for €1.6 billion in damages.

UBS, which was ordered to post €1.1 billion in bail, had denied the charges and said its operations complied with Swiss law.

It also said that it was “unaware” that some French clients had failed to declare assets in Switzerland, and that prosecutors have not produced any proof, such as client names or account numbers, to back up their fraud claims.

The case was closely watched by industry executives at a time when Paris and other European capitals are hoping to lure multinational banks from London as Brexit looms.