French judges ordered UBS Group AG on Wednesday to pay a record €3.7 billion ($4.2 billion) fine for helping wealthy clients in France evade taxes, as Switzerland’s largest bank struggles to turn the page on legal entanglements stemming from its core wealth-management business.

Judges in Paris found the Zurich-based bank guilty of illegally recruiting clients in France and helping them to launder money that wasn’t declared to French fiscal authorities. In handing down the largest-ever fine in France, the judges described the lender’s crimes as “exceptionally serious.”

“The conviction is not supported by any concrete evidence,” UBS said, adding that it planned to appeal the decision.

The trial cast a spotlight on how UBS used its operations in France to identify clients interested in moving funds to Switzerland to avoid scrutiny from French tax authorities. UBS bankers in Switzerland used methods “worthy of James Bond,” prosecutors argued in court, to travel surreptitiously to France and meet with French clients at parties and other events organized by UBS bankers in France.

UBS denied wrongdoing in court, arguing that prosecutors based their case solely on allegations from former employees who didn’t testify during the trial. The lender also argued the money-laundering charges were baseless because prosecutors had not proven the underlying crime of tax fraud by its French clientele.