Charles-Stuart Forbes was born in 1856 in Geneva, Switzerland to American parents. In 1887, he studied with Carolus-Duran in Paris, France. During these years he exhibited at the Paris Salon (1887-1889); in 1891 he exhibited in the Salon of the Société Nationale des Beaux Arts in Paris. The society was founded in 1880s and began holding its own spring Salon (rivaling the original official Salon) in the Palais des Beaux Arts on the Champ-de-Mars. There he met and became a close fiend and colleague of another famous American expatriate artist by the name of John Singer Sargent (1856-1925). In 1881, along with Sargent and three other artists (Ralph Curtis, Julian Pennington and Julian Story) they painted Robert Browning in at Browning son's Palazzo Rezzonico in Venice. Sargent painted Forbes portrait, circa 1889: it hangs in the Henry E. Huntington Library and Art Gallery San Marino, California.
It seems that Mr. Forbes was in the United States by the turn of the century; it looks like he went first to Boston, where he worked with the Boston Art Club and than on to New York.
Exposition Universelle de Paris, 1889
Who Was Who in American Art, v.1
Thieme / Becker
American Art at the 19th century Paris Salons
Paris 1889, American Artists at the Universal Exposition