Florimond Claude, comte de Mercy-Argenteau (20 April 1727 – 25 August 1794) was an Austrian diplomat, statesman of French noble ancestry, in the service of the Holy Roman Empire.

He entered the diplomatic service of Austria in Paris in the train of Reichsfürst Wenzel Anton of Kaunitz-Rietberg.

In Paris, his first work was to strengthen the Franco-Austrian alliance, which was cemented in 1770 by the marriage of the Dauphin, afterwards Louis XVI, with Archduchess Maria Antonia Josepha Johanna of Austria, youngest daughter of Empress Maria Theresa, afterwards known as Queen Marie Antoinette.

Although at first in favour of moderate courses, Mercy-Argenteau supported the action of Austria in making war upon its former ally after the outbreak of the French Revolution, and in July 1794, he was appointed Austrian ambassador to Britain, but he died a few days after his arrival in London.

[2] Florimond Claude never married, but had an extramarital affair with an opera singer from Palais Garnier, Claude Josèphe Rosalie Levasseur, Baronne de l'empire (1749-1826), daughter of Jean-Baptiste Levasseur.