After studying Economics and Public Affairs, he joined the Foreign Affairs ministry and served in Peru, Mexico, Canada and the United States and, later, as spokesman to the French Mission to the United Nations in New York.
He became Chief of Staff to the Ambassador of France in Washington before returning to Paris in 2002 as Deputy Chief and Chief of Staff to two Foreign Ministers. He spent four years as Chief of Protocol to two French Prime Ministers and was appointed Ambassador to Panama and, later, Permanent Observer to the Organization of American States in Washington.
From 2013 to 2016, as Secretary General in charge of the preparation of COP21, he seconded Foreign Minister Laurent Fabius as France built the Paris Agreement on Climate Change. He was then appointed Ambassador to Argentina. On November 4, 2019, Guignard was appointed as Special Envoy for France to the Alliance for the Conservation of Rainforest.
An active member of the French Association for the UN, he is also an independent local counselor for the City of Abzac in the Southwest of France. He has written a number of novels and essays.
