De Staël's painting career spans roughly 15 years (from 1940) and produced more than a thousand paintings. His work shows the influence of Gustave Courbet, Paul Cézanne, Henri Matisse, Pablo Picasso (especially Picasso in his Blue and Rose periods), Georges Braque, Fernand Léger and Chaim Soutine, as well as of the Dutch masters Rembrandt, Vermeer and Hercules Seghers. During the 1940s and beginning in representation (especially landscapes, but also still lifes, and portraits), de Staël moved further and further toward abstraction. Evolving his own highly distinctive and abstract style, which bears comparison with the near-contemporary American Abstract Expressionist movement, and French Tachisme, but which he developed independently of them. Typically his paintings contained block-like slabs of colour, emerging as if struggling against one another across the surface of the image. Accordingly, when a Rothko painting was paired with one by Nicolas de Staël in the show of young French and American painters, Rothko commented to William Seitz (in 1952): "Blobs vs. blocks. They both begin with ‘b.‘ Comparisons are false!"". In fact, according to de Staël himself, he turned to his "abstracting" because he "found it awkward to paint an object as a likeness because of the awkwardness I felt when faced with the infinite multitude of coexisting objects in any single object".
The French New Wave filmmaker Jean-Luc Godard has stated that de Staël is his favorite painter, and the use of primary colors in his film Pierrot Le Fou was strongly influenced by de Staël's work.Wikipedia