The source said the prosecutor had also requested UBS France, the bank's French arm, go on trial for complicity.

A spokeswoman for UBS had no immediate comment.

French investigating magistrates now have a month to decide whether or not UBS should face judges.

UBS was placed under formal examination in 2014. At the time, investigating judges ordered the company to pay a 1.1 billion euro ($1.21 billion) bail.

(Reporting by Chine Labbe, writing by Matthias Blamont; Editing by Richard Lough)