In the middle of all the artistic confluences of Montmartre in the 1920s, Gen Paul starts to search for his own road of artistic expression, distinct from his contemporaries. He becomes one of the first French expressionists, developing his own manner, dynamic and free. He searches for the sources of his art not just in the vibrant local scene and in the post-impressionist works of his forefathers, such as Van Gogh or Toulouse-Lautrec, but also in the Museum of Prado, where he encounters the works of Goya, El Greco and Vélasquez – Gen Paul will be an avid traveller all his life.

Unlike other expressionists, whose palette is more sober, Gen Paul makes audacious use of colour harmonies and contrasts in his works. His painting is marked by the gestural nature of his brushstrokes, which create a singular feeling of rhythm and movement in his works. It is this gestural style that leads critics to place him as one of the precursors of Action Painting and Abstract Expressionism in the 1950s, together with Chaïm Soutine.