Cologne's public prosecutor and tax authorities are examining claims, which have come to light via the leaked Panama Papers, alleging that leading German private bank Berenberg helped clients to evade tax, news magazine Der Spiegel reported on Saturday.
German Finance Minister Wolfgang Schäuble on Sunday pleaded for countries to work together in the fight against tax cheats and money launderers by sharing national lists naming the beneficiaries of shell companies.
The German government on Monday said it hoped the revelations from the so-called "Panama Papers" will spur global efforts to combat tax evasion and money laundering.
Dozens of world leaders, politicians, celebrities and sports stars are fidgeting uncomfortably on their chairs after a German newspaper unveiled details of their offshore activities.
Forget Switzerland; some of Germany's richest families, including Porsche and coffee giant Jacobs, have far-flung businesses registered in oft-forgotten tax haven Panama, it emerged on Wednesday.