Hôtel Drouot will be auctioning four drawings by Jean Auguste Dominique Ingres (1780-1867), the French Neoclassical painter, on March 24.
These artworks are particularly important, in that they chronicle a friendship regarded as one of the most important and happiest of the artist's life.
In Rome, 1810, Marcotte d'Argenteuil was a high official in the imperial water and forestry administration.
The art-loving official was on the lookout for a portraitist. He was eventually introduced to Ingres via a mutual friend, which resulted in a series of artworks.
Among the works is a signed pencil portrait of Charles Marie Jean Baptiste (aka Marcotte d'Argenteuil), dated 1928. It is estimated at €300,000-400,000.
Another portrait of Marcotte d'Argenteuil - signed and dedicated by Ingres to "good friend" Mr Marcotte, and dated 1851 - will auction with a pre-sale value of €150,000-200,000.
Pre-sale viewings will be held on March 23-24, prior to the afternoon sale on the second day.