(August 7, 1862 - July 1939) was an Intimist painter born to a French family in Port Louis, Mauritius. In 1870 he and his family settled in Dunkirk. Le Sidaner received most of his tutelage from the École des Beaux-Arts under the instruction of Alexandre Cabanel but later broke away due to artistic differences.
He travelled extensively throughout France and also visited many cities around the globe such as London, New York, Venice and Paris as well as some small villages throughout Europe. Le Sidaner exhibited at the Salon, the Galeries Georges Petit in Paris and the Goupil Gallery in London. He lived in Gerberoy, France.
Le Sidaner's work was mentioned in Marcel Proust's novel In Search of Lost Time. In Sodom and Gomorrah, the narrator mentions that an eminent barrister from Paris had devoted his income to collecting the paintings of the "highly distinguished" but "not great" Le Sidaner.