The brothers Stéphane and Gaspard Bourgeois were art dealers in Cologne. Their collection was sold in that city in 1905, after both brothers had died--Stéphane in 1899, Gaspard in 1904.
Gaspard's son, Stephan Bourgeois (1881-1964) went into business with relatives in the Steinmeyer family, establishing an art dealership in Cologne in 1906, Steinmeyer and Bourgeois. This lasted until about 1910, when Stephan departed and most of the stock remained with Steinmeyer.
Stéphane's daughter married the dealer Leo Nardus in 1904. Nardus went into business with Stephan in a gallery called Nardus & Bourgeois that was active until about 1924.
Stephan Bourgeois came to the United States and became a citizen by 1926. He opened a gallery first under his own name and later known as Bourgeois Galleries.
Stephan Bourgeois' papers are at the Archives of American Art, Smithsonian Institution.