In a letter that stated that the investigating judge "envisages placing Danske Bank under formal investigation", the bank was summoned to interviews in an ongoing investigation into organised money laundering.

Danske Bank was initially placed under investigation by a Paris court in relation to suspicions of money laundering concerning transactions at its Estonian branch between 2008 and 2011, but in January last year the court changed its status to that of "assisted witness," a Danske spokesman said on Thursday.

Bill Browder, founder and CEO of investment fund Hermitage Capital Management, said on Thursday he had asked French authorities to investigate Danske Bank over alleged money laundering, rather than treating it as a witness. It was not immediately clear if the summons was linked to Browder's request.

(Reporting by Teis Jensen; Editing by Kirsten Donovan)