La Barre de Nanteuil started his career serving in the Middle East before being posted as the Ambassador to the Netherlands in 1976 and 1977.[4] He was quickly transferred to represent France as the Permanent Representative to the European Union (EU),[5] serving until 1981. He was posted to New York as President of the United Nations Security Council[6] and then back to Brussels as the Permanent Representative to the EU,[7] before being promoted Ambassador to the United Kingdom. He served in London from 1986 until retiring from French diplomatic circles in 1990.[8]
La Barre de Nanteuil subsequently was Chairman of Les Echos Group from 1991 until 2003.
He had two children and lived in Paris with his second wife Hedwige, née Frèrejean de Chavagneux.[9]
