Niersbach takes political responsibility for a controversial $7.22m payment to FIFA.
German daily Sueddeutsche Zeitung (SZ) reports that the FBI has opened a corruption investigation into the awarding of the 2006 World Cup to Germany.
SZ said it was told by “sources close to FIFA” that the FBI was concerned about a suspect payment made by the German football federation to FIFA before the tournament was awarded.
The DFB said the money was a loan of 10 million Swiss francs – the equivalent of $7.22m – from then-Adidas boss Robert Louis-Dreyfus to FIFA in 2002 to obtain a large grant for the World Cup organising committee.
It is unclear who exactly received the money, however.
The payment is also the target of a tax evasion investigation by German and Swiss authorities.