The Audi employee was arrested on Monday, at the behest of Munich prosecutors, a spokeswoman for the Munich prosecutors office said on Friday. When asked if the arrest was at the request of US authorities, the spokeswoman said it was not. She did not give the name of the person.
Munich prosecutors declined to comment on whether the arrested person is a current or former Audi employee.
Audi and parent Volkswagen both declined to comment.
On Thursday, the US Justice Department said it charged former manager Giovanni Pamio with directing Audi employees to design software to cheat US emissions tests in thousands of Audi diesel cars.
Audi is a division of Volkswagen Group.
The Munich prosecutor's office said the Audi employee was brought before a judge on Tuesday and was now being held in custody.
The spokeswoman declined to discuss the possibility of the detained person being extradited to another country or comment on whether Munich prosecutors were in touch with US authorities.
The German arrest was part of a wider probe into fraud and false advertising and is a consequence of "findings following searches," the spokeswoman said.
In March, Munich prosecutors searched the offices of Jones Day, the lawfirm Volkswagen had hired to lead an internal investigation into its emissions scandal and Audi's headquarters.
Volkswagen condemned the searches at the time, and never published the full findings of its internal investigation which was being conducted by Jones Day.
The raids by Munich prosecutors in March sought to shed light on who was involved in the designing and using illicit software used in 80,000 VW, Audi and Porsche cars with bigger 3.0-liter engines.
No members of the Audi management board are being personally investigated as part of that probe, the spokeswoman said on Friday.
In the criminal complaint released by US authorities on Thursday, US prosecutors charged that Pamio ignored or suppressed warnings by certain Audi engineers that the pollution control systems being used on the brand's diesel engines violated US clean air rules.
US prosecutors said Pamio had ordered subordinates to send false information to American regulators stating that Audi's "clean diesels" did not use technology designed to cheat federal pollution tests.
Neither Pamio nor his representatives could be reached for comment on Friday.
Reporting by Edward Taylor, Andreas Cremer and Jan Schwartz.