Although fascinated by dream-like states of the nomadic unconscious and other imaginary worlds of the "marvelous", a dispute with Breton in 1929 got him expelled from the movement, and prompted him to contribute to Un Cadavre, an anti-Breton pamphlet.
After the break with Surrealism, Baron became associated with Georges Bataille and Documents, in which he published a short essay on "Crustaceans for the Critical Dictionary" (1929, issue 6), an article on the sculptor Jacques Lipchitz (1930, issue 1), and a poem dedicated to Picasso, "Flames" (1930, issue 3).
He later collaborated on a number of reviews such as Le Voyage en Grèce, La Critique Sociale and Minotaure.