In the case of Chowdury and Others v. Greece, the Court found a violation of the prohibition of forced labour. The applicants, 42 undocumented Bangladeshis, had been recruited between October 2012 and February 2013 to pick strawberries in a farm in Greece. Their employer had paid them no wages and forced them to work under extreme physical conditions, watched over by armed guards.
The Court held that labour exploitation was one of the aspects of trafficking in human beings. It found that Greece had failed in its obligations to prevent such situations, protect the victims, conduct an effective investigation into the offences committed and penalise those responsible for the people trafficking.

source: the European court of human rights website