The objective of this project is to describe and analyse the effectiveness and the functioning of possible mechanisms regarding (joint and several) liability with regard to the protection of workers who work in a (sub)contracting situation in the European Union. The study wants to investigate whether a possible European instrument regarding (joint and several) liability is advisable and, furthermore, wants to formulate recommendations in order to create a turn in the protection of workers who work in (sub)contracting situations, in particular in cross-border situations.