Four men aged between 59 and 75 have been convicted after organising sauna sessions which became steamier than they should have.
A shocked bather walked into the steam room to discover the four taking part in a sex game.
Police were called to reports that they were pleasuring each other at the Alster public baths in Hamburg, the Daily Mail reports.
The men, named Ingo R, aged 75, Fred G, 75, Norbert L, 63, and Victor H, 59, were all fined more than €1500 (NZ$2300) Die Welt reports.
They were convicted of arousing a public scandal, the newspaper states.
It happened at 12.30pm on February 22 last year.
Ingo R claimed he was not involved in the orgy, stating he had not been to the baths for a decade.
He complained: 'I have been punished because the police can't do their jobs properly.'