Marc Finaud started his career at the French Ministry of Foreign Affairs at the Military Cooperation Division in 1977. From 1977 until 1978, he served as Vice-Consul at the French Consulate-General in Leningrad (USSR). From 1979 until 1982, he worked at the Directorate for Europe (Conference on Security and Cooperation in Europe (CSCE)) in Paris. From 1982 until 1983 he served as Chief of Staff of the Secretary-General of the Ministry of Foreign Affairs, before being appointed First Secretary at the French Embassy in Warsaw. From 1989 until 1993 he was Second Counsellor at the French Delegation to the Conference on Disarmament in Geneva (dealing with nuclear and outer space issues as well as conventional and biological weapons) and a member of the French Delegation to the First Committee of the General Assembly of the United Nations in New York.
From 1993 until 1996 he was appointed Head of the Information Department (and alternate spokesman) of the Foreign Ministry in Paris. Following this from 1995 until 1996, he was a lecturer on arms control and disarmament for a post-graduate course at the Marne-la-Vallée University. In 1996 he was appointed Deputy Head of Mission at the French Embassy in Tel Aviv, Israel, where he joined the Team of Negotiators of the EU Special Envoy to the Middle East. In January 2001, he was transferred to Sydney, Australia to serve as Consul-General for France.