The husband and wife were questioned by police after officers broke up one of their sex parties in a Frankfurt hotel room on Wednesday evening. There were five people present including the couple.
The pair from Brandenburg are accused of failing to declare takings for the last eight years from their pricey events where entry cost €180 ($247) per person.
They now owe the treasury almost €1 million in tax payments from earnings made from around 450 sex parties organized since 2005, authorities said.
The man, aged 51, and woman, aged 49, organized parties across the country, a Frankfurt police spokesman told The Local on Friday.
He added that the couple had been barred from the hotel.
Both of the organizers claimed Hartz IV unemployment benefit and are officially registered as unemployed.