[Thanks to Jonathan Moffat of Outer Temple Chambers for preparing this case summary]
Does Article 45 TFEU (freedom of movement for workers) preclude legislation of a federated entity of a Member State which requires all employers whose established place of business is located in that entity's territory to draft cross-border employment contracts exclusively in that entity's official language failing which they are to be declared null and void?
Yes, held the CJEU in Anton Las v PSA Antwerp NV, on proportionality grounds.
The employee asserted that as the relevant contract with the employer was drafted in English rather than Dutch it should be deemed null and void, in which case the parties were not bound by the term concerning severance payments and that he was entitled to greater compensation on his dismissal. The employer contended that the relevant legislation infringed Article 45 TFEU and that the contract should be respected.
The CJEU held that Belgium's three objectives, the first of which was to promote and encourage the use of Dutch, constituted legitimate interests which, in principle, justified a restriction on Article 45 TFEU. However, the relevant legislation was not proportionate. Legislation which also permitted the drafting of an authentic version of such contracts in a language known to all parties concerned was less prejudicial to free movement while being appropriate to secure the pursued objectives