During his convalescence, he returned to painting, and at Le Bateau-Lavoir he became friends with Juan Gris who helped him a great deal.
Due to the dynamism and motion inherent in his paintings, some consider Paul to be the first action painter, a precursor to the abstract expressionists of the 1950s.
[citation needed] Paul died at the Pitié-Salpêtrière Hospital in Paris on 30 April 1975 and was interred in the Cimetière Saint-Vincent in Montmartre.
A great many of his works remain in private hands but a number of his important pieces can be found at museums in France and in other parts of Europe.
The paintings of 1930s reflect a more somber mood with precise lines and carefully chosen colors and an emphasis of rhythm over motion.