In 2002, Matt completed a clerkship in the cabinet of Judge Antonio Mario La Pergola, at the Cour de justice des Communautés européennes (Court of Justice of the European Communities) in Luxembourg City, Luxembourg. While serving at the Cour de justice, Matt had the opportunity to work on numerous cases, including appeals of antidumping determinations imposed by the European Commission, disputes between European Union member states involving intra-EU fishing quotas, the application of the VAT Directive, and the extra-territorial effects of member state bank secrecy laws under the Treaty on European Union.