Franz Perrez is Director-General of the Directorate of International Law at the Federal Department of Foreign Affairs (FDFA), Switzerland. He is responsible for the development and interpretation of international law and ensuring that Switzerland's strategic rights are respected abroad. As a member of the FDFA senior management, Mr Perrez is also jointly responsible for the FDFA's strategic approach and advises the Federal Council, Switzerland's representatives abroad and other Federal Administration offices on international law issues.

Prior to his new role Mr Perrez was appointed Switzerland's Ambassador for the Environment and Head of the International Affairs Division at the Federal Office for the Environment (FOEN) in 2010. In this capacity, he headed the Swiss delegations to international environmental and climate negotiations for thirteen years.

After studying law in Bern and Paris, Mr Perrez worked at the FDFA's Directorate of International Law from 1993 to 1995. He went on to study at New York University, where he gained a master of laws focusing on international law and completed a PhD thesis on the topic of sovereignty as a principle of cooperation. On returning to Switzerland, he took up a position at the World Trade Organization (WTO) Division of the State Secretariat for Economic Affairs, before joining the FOEN in 2001.

Mr Perrez has proven expertise in international law. He has widely published in the area of international environmental law, international environmental governance, the relationship between trade and the environment, and public international law. Since 2008, Mr Perrez has also lectured on international environmental law at the University of Bern School of Law. He served as a panellist on the newest WTO tuna–dolphin dispute between Mexico and the United States, and as Switzerland's Ambassador for the Environment and Chief Negotiator for Environmental Issues, namely climate change, biodiversity, chemicals and waste, he led the Swiss delegation to the Rio+20 conference and to the Paris Climate Change Conference in 2015. He was President of the Basel Convention (COP 11 in 2013) and President of the Rotterdam Convention (COP 8 in 2017) and facilitated the negotiations on mitigation of the Paris Agreement. Through his work within and outside of Switzerland, he has built strong networks around the world and within the Federal Administration.