In 2012, an arbitral award condemned Slovakia for the breach of a bilateral investment treaty (BIT) signed with the Netherlands. Slovakia appealed the High Court of Frankfurt and the Supreme Court to contest the compatibility between the Intra-EU BIT Dispute Resolution mechanisms (ISDS) and the European law. The German jurisdictions have submitted a reference to the CJEU for a preliminary ruling. The Advocate general – Pr. Melchior Wathelet – has given his observations. According to him, arbitral tribunals, as state Courts under the European law, shall be able to request several preliminary rulings to the CJEU. Besides, Intra-EU’s ISDS are compatible with the European law: they do not create unbalanced treatments between EU State member citizens and they do not jeopardize the autonomy of the EU judicial system.