Paul Durand-Ruel
Petit had an intense rivalry with art dealer Paul Durand-Ruel (1831–1922). Durand-Ruel took over his business from his father in 1865. The Petit and Durand-Ruel galleries had been the top two firms in Paris dating back to the 1850s. Paul Durand-Ruel was 25 years older than Petit and had become an advocate of the Impressionists as early as 1870.