Five people have gone on trial in Germany for allegedly trafficking up to 200 Thai women and forcing them to work in a nationwide network of brothels.
The four Thai women and a German man were arrested last year in what was dubbed the biggest mass search in the history of the federal police.
The victims, several of whom are transgender, allegedly had passports confiscated and salaries withheld.
The trial began on Tuesday at a court in the western town of Hanau.
Prosecutors say the defendants, aged between 49 and 60, belonged to a network that operated brothels in which women were forced to work under a "rotation system".
The victims were smuggled into the country on fake tourist visas and initially forced to work in three brothels in the western city of Siegen before being moved elsewhere, it is alleged.
Prostitution is legal in Germany, but the suspects allegedly did not pay the women.
Prosecutors say the suspects took the money as payment for entry into Europe's border-free Schengen zone and for board and lodging.
The five are facing charges of trafficking and exploitation. Two of the defendants have also been charged with tax evasion.
Last year's mass police operation came after German MPs tightened laws to crack down on exploitation.
Under the rules, sex workers are required to register with local authorities and it is illegal to knowingly hire the services of people forced into prostitution.