Louis de Noailles "refused to emigrate during the (French) Revolution but escaped the fate of most noblemen by dying in August 1793 before the Terror reached its height. On July 22, 1793 his wife, the aged Duchess of Noalles, was executed" along with her daughter-in-law, the Duchess d'Ayen and her granddaughter, the Vicountess of Noailles. Louis was made marshall of France (Noailles) in 1775.
SOURCES:"Ancestors/Descendants of Royal Lines" (Contributors: M. Thompson, Reynaud de Paysac, H.R. Moser <Burke Peerage>), F.L. Jacquier, O.Guionneau, E. Polti, A.Terlinden <Genealogy of the existing British Peerage, 1842, L. Orlandini, R. Dewkinandan, and E. Lodge>).
Also: "Ancestors of Valery Giscard d'Estaing", http://www.geneastar.org