His nickname was given not for his art but for the many years he worked as a customs inspector.  
The year after he died, a memorial exhibition of his works was organized by Wilhelm Uhde [oo-duh], who also wrote the first biography of this artist.  His technique always involved painting individual colors one by one and painting from the top of the canvas to the bottom.  His portraits include those of Pierre Loti and Leon-Paul Fargue, as well as a self-portrait with a lamp.  Whimsy and disproportion typify such canvases as Unpleasant Surprise, The Merry Jesters, Boy on the Rocks and The Football Players.  Yet, it is the exoticism of such paintings as The Dream and The Snake Charmer that set him apart.  His nickname was given not for his art but for the many years he worked as a customs inspector.  For 10 points, name this man who often painted jungle scenes featuring lions and tigers, such as in his magnum opus The Sleeping Gypsy.
The year after he died, a memorial exhibition of his works was organized by Wilhelm Uhde [oo-duh], who also wrote the first biography of this artist.  
Henri Rousseau (or Le Douanier Rousseau) [Douanier meaning customs inspector]