Due to generally much lower tax rates than in Western European countries, temporary workers (especially from Eastern European countries) are covered by social security in the country of establishment of the temporary employment agency and not in the country of deployment.
Which national social security law is applicable to temporary agency workers working across borders? The European Court of Justice (ECJ) has now dealt with this explosive question (judgment of 03.06.2021, ref. C-784/19).
In its decision of 02.04.2020, the ECJ held that Regulation EC 647/2005 must be interpreted as meaning that the courts of a Member State, which are involved in legal proceedings against an employer who has fraudulently obtained or used E101 or A1 certificates issued to employees working in the Member State,