From the Sotheby’s catalog:

“The scene depicted is a picnic of French gardistes in the Bois de Boulogne after their parade on the occasion of quatorze juillet. In the background is the sunlit area of the horse path of Longchamp, where the parade took place. Hoynck van Papendrecht witnessed this event during his trip to Paris, in 1904. His impressions were recorded in numerous sketches, which formed the basis for the present picture, executed two years later.”

See: Jan Hoynck van Papendrecht. Picnic after the Parade, Bois de Boulogne. Oil on canvas (1906)