PARIS (Reuters) - France's financial prosecutor has requested a trial for HSBC Holdings and its Swiss private banking unit on suspicions it helped customers dodge taxes in 2006-2007, a source familiar with the matter told Reuters.

"We  take  note  of  the  recommendation... and will continue to defend ourselves vigorously," HSBC said in an emailed comment to Reuters.

The bank was put under formal investigation last year. It will be up to investigating magistrates to decide on whether it should stand trial.

Magistrates had previously estimated the Swiss arm's alleged fraud at around 2.2 billion euros (1.66 billion pound).

HSBC has admitted failings in controls at the Swiss private bank, but denied knowledge of wrongdoing.

(Reporting by Chine Labbe; Additional reporting by Matthias Blamont in Paris and Lawrence White in London; Writing by Maya Nikolaeva; Editing by Andrew Callus)