Nine hundred police officers have taken part in a raid on one of Germany's biggest brothels in Berlin, making six arrests over alleged human trafficking and tax fraud.
The operation follows months of investigation into the Artemis brothel.
Brothel managers are accused of evading some €17.5m (£14m; $19.7m) in social security payments since 2006.
Prosecutors allege that staff at Artemis were forced to pretend to be self-employed to avoid the payments.
Police say the raid was conducted in cooperation with customs officials and tax fraud investigators.
Germany legalised prostitution in 2002, creating an industry now thought to be worth approximately €16bn per year.
So-called "mega-brothels" are common, attracting tourists from neighbouring countries with stricter laws, and sex workers from Eastern Europe.
The number of prostitutes in Germany is thought to have doubled to 400,000 over the last 20 years.