There was a distinct difference between Kahnweiler’s Cubists and the Salon Cubists. Prior to 1914, Picasso, Braque, Gris and Léger (to a lesser extent) gained the support of a single committed art dealer in Paris, Daniel-Henry Kahnweiler, who guaranteed them an annual income for the exclusive right to buy their works. Kahnweiler sold only to a small circle of connoisseurs. His support gave his artists the freedom to experiment in relative privacy. Picasso worked in <answer>Montmartre</answer> until 1912, while Braque and Gris remained there until after the First World War. Léger was based in Montparnasse.
Where did Picassos work until 1912? 
Montmartre