Financial investigators are demanding that the world's biggest wealth management bank pay the whole of the bail it has deposited as a fine for touting for rich clients who wanted to dodge paying tax in France between 2004 and 2011, according to the Journal du Dimanche.
They estimate that the country lost 10 billion euros in tax because of the bank's action.
"The figure is unthinkable both for our shareholders and in relation to what we have negotiated with other legal authorities," UBS's legal chief Markus Dietlhelm told the paper. "It's not at all the market price."
Fine could be higher
UBS lost an appeal against the unprecedentedly high bail figure, set in 2014, to the European Court of Human Rights, which ruled that it was a provisional measure that did not prejudge the case's outcome.
Two judges in charge of the case are to make the demand at the beginning of the week, the Journal du Dimanche says.
Although the figure is high, it could legally be much higher.
A fine for money-laundering can be equal to half the value of the funds concerned, according to French law
French tax officials netted 21.2 billion euros from tax dodgers in 2015, a quarter of it from big companies.