Authorities in Germany, the company's home market, issued the penalty as the company's chief executive at the time the so-called dieselgate scandal broke remains in prison, pending the findings of an investigation into the extent of his personal involvement.
Audi is part of the Volkswagen (Xetra: 766400 - news) (VW) group which admitted three years ago that it had fitted a "defeat" device to 11 million cars sold worldwide that lowered nitrogen oxide pollutants in diesel engines undergoing emission checks.
The scandal has so far cost it well over $30bn - the bulk of that sum in compensation and fines in the United States.
While the VW group has admitted 1.2 million vehicles were affected in the UK, it has refused similar payouts to owners on the grounds no EU law was broken through the use of the software.
German prosecutors said their fine reflected neglect by Audi management between 2004 and 2018 and, particularly, the extent of the economic gains enjoyed by the company through the cheating.
The company said in response: "Audi accepts the fine and, by doing so, admits its responsibility."
Rupert Stadler, who was detained in Germany in June over fears he may try to obstruct the inquiry, has led Audi since 2007 but since been replaced on an interim basis.
The head of VW at the time dieselgate came to light in 2015, Martin Winterkorn, is facing criminal charges in the US but neither he, nor other executives named in court papers, are likely to see the inside of a courtroom because of the lack of extradition arrangements between Germany and the US.