The 11th and 13th arrondisements are a pretty good bet. Mosey on by Le Mur, 107 Oberkampf on May 25 to gaze at David Walker in action. This is part of Le M.U.R. de L’ART exhibition, the association promoting ephemeral street art at this fixed position. Every two weeks a new artwork replaces the previous, the artist featured being given a stipend of 500 euros to cover travel and material expenses.
A few street artist sites for you to explore: