Charnay was born in Charlieu in the Loire, and moved to Paris in around 1865. He studied briefly in the studios of Feyen-Perrin and Pils, but was mainly self-taught, painting from nature and copying works by Claude, Poussin and Daubigny. He exhibited at the Salon from 1865. From 1871 he painted increasingly in the Forest of Fontainebleau. A painter and etcher of landscapes, he specialised in the depiction of old châteaux and their surrounding parks.