Over 100 suspects have been detained and seven arrested in raids across Germany targeting forced prostitution and human trafficking.
Some 1,500 officers were involved in the raids in 12 out of Germany's 16 states.
The operation - the biggest of its kind in Germany - was aimed at stopping a "national network" of organised crime, Interior Minister Horst Seehofer said.
Police searched 62 brothels, offices and homes in a crackdown on suspected human trafficking in connection with a Thai prostitution ring.
Prosecutors suspect that a number of people, led by a 59-year-old Thai woman and her 62-year-old German partner, brought women and transsexuals from Thailand to Germany on tourist visas and forced them into prostitution.
The woman is suspected of keeping money that the prostitutes earned, supposedly to cover the cost of bringing them to Germany as well as for room and board at several brothels in the western town of Siegen, and of eventually passing them on to brothels elsewhere.
"The investigation has so far identified a total of 32 women and transsexuals who were smuggled into Germany by the suspects and who allegedly worked in the brothels as prostitutes," the prosecutor's office said.
