He was from the younger branch of the Lomenie Flavignac family originating in Limousin, which became in the seventeenth century the house of Brienne.

Appointed Secretary of State for War from 1787 to 1788, he was guillotined on 21 Floreal Year II (10 May 1794) with four other members of his family and Élisabeth de France.

He was Marquis de Moy and lord of Vendeuil by marrying Etiennette Fizeau Clémont, who was the daughter of a wealthy mill owner in Saint-Quentin.

He rebuilt the castle in Brienne-le-Château, and bought in Paris a beautiful town house in the Rue Saint-Dominique called Hôtel de Brienne, current residence of the Minister of the Army.

Athanase de Brienne and Etiennette Fizeaux had a son, François-Alexandre-Antoine Lomenie, Vicomte de Brienne, commanding officer of the 12th regiment of chasseur à cheval, who was guillotined on 21 Floréal Year II at the age of 36 years.