File talk:Greuze - Renaud César de Choiseul Praslin - 1775.jpg

I have not seen the research that has led to the conclusion that this is a painting by Elisabeth Louise Vigée (later Vigée Le Brun), or that the sitter is a marquis de Choiseul. However, Vigée Le Brun includes a portrait of marquis de Choiseul on her list of paintings, for the years 1768-72. Furthermore, in Letter II of her memoirs (Souvenirs), she discusses the fact that in her teen years, some men who came to sit for her would attempt to gaze longingly at her, and it upset her when the marquis de Choiseul did so, as he had just married a beautiful 16-year-old American girl, mademoiselle Rabi.

Page 245-246 of Histoire généalogique et chronologique de la Maison de France, by Anselme de Saint-Marie (1879), gives us the identity of this man and his beautiful young bride (who tragically did not live long):

Charles Antoine Etienne de Choiseul-Beaupré, seigneur de Sommeville, called marquis de Choiseul-Beaupré, was born in Santa Domingo on 10 July 1739, and was still alive in 1817. He was colonel à la suite du régiment Dauphin (étranger) en 1763, puis lieutenant général. His parents were Antoine-Nicolas de Choiseul-Beaupré (1716-1760) and Renée-Marie-Michelle de Beauval. This marquis de Choiseul was married twice. On 11 August 1770, in the parish of St. Eustace in Paris, he married Louise Raby, a daughter of Jean-Baptiste Raby & Marthe Bourgeois. Tragically, she died in Paris on 24 October 1772, with her age given as 17. He married again, on 16 March 1775 at St. Georges-sur-Loire, to Françoise Elizabeth Marie Joséphe Walsh (born at Serrant and baptized at St. Georges-sur-Loire 15th October 1758), with whom he had seven children. His second wife died in 1793.

Therefore, Mlle Vigée would have painted him in late 1770 or early 1771.