Under Article 21(1)(b)(i) and (2) of Regulation (EU) No 1215/2012, an employee may sue in the courts for the last place where or from where he or she habitually carried out his or her work a person - whether or not domiciled in a Member State - with whom the employee has no formal employment contract, if that person is directly liable to the employee under a letter of comfort that was a prerequisite for concluding the employment contract with a third party, provided there is a hierarchical relationship between that person and the employee.

Where the conditions for Article 21(2) are satisfied, the reservation in Article 6(1) concerning the application of Article 21(2) prevents a Member State court from applying its national jurisdiction rules, even if those rules are more favourable to the employee. Where the conditions for Article 21(2) or any other provision listed in Article 6(1) are not satisfied, Article 6(1) allows the court to apply those national rules to determine jurisdiction.