This report aims to deepen the understanding of the micro aspects of the use of the euro in international trade invoicing and/or settlement. What determines the use of a currency in the invoicing of international trade? Is the euro increasingly used as an invoicing currency in international trade? What are the obstacles to the use of the euro in trade invoicing? This report collates existing analyses on the possible obstacles for using the euro in international trade and discusses the theoretical and empirical literature addressing these questions.