Clifford Chance’s Frankfurt office was raided Feb. 27 by German authorities seeking files on a banking client that is caught up in the so-called CumEx tax saga.

The search and subsequent handing over of files was not against the firm itself, but rather ABN Amro, which the firm is advising in relation to CumEx misconduct, according to a person with knowledge of the matter. CumEx misconduct involves allegations against a network of banks, stock traders and lawyers that they unlawfully obtained billions from European treasuries through suspected fraud and speculation involving taxes.