His earliest works were impressionistic, but after seeing the work exhibited by the Fauves in 1905 Braque adopted a Fauvist style. The Fauves, a group that included Henri Matisse and Andre Derain among others, used brilliant colors and loose structures of forms to capture the most intense emotional response. Braque worked most closely with the artists Raoul Dufy and Othon Friesz, who shared Braque's hometown of Le Havre, to develop a somewhat more subdued Fauvist style. In 1906, Braque traveled with Friesz to L'Estaque, to Antwerp, and home to Le Havre to paint.
In May 1907, Braque successfully exhibited works in the Fauve style in the Salon des Indépendants. The same year, Braque's style began a slow evolution as he came under the strong influence of Paul Cézanne, who died in 1906, and whose works were exhibited in Paris for the first time in a large scale museum-like retrospective in September 1907. The 1907 Cezanne retrospective at the Salon d'Automne greatly impacted the direction that the avant-garde in Paris took, leading to the advent of Cubism.
Braque's paintings of 1908–1913 began to reflect his new interest in geometry and simultaneous perspective. He conducted an intense study of the effects of light and perspective and the technical means that painters use to represent these effects, appearing to question the most standard of artistic conventions. In his village scenes, for example, Braque frequently reduced an architectural structure to a geometric form approximating a cube, yet rendered its shading so that it looked both flat and three-dimensional. In this way Braque called attention to the very nature of visual illusion and artistic representation.
Beginning in 1909, Braque began to work closely with Pablo Picasso who had been developing a similar approach to painting. The invention of Cubism was a joint effort between Picasso and Braque, then residents of Montmartre, Paris. These artists were the movement's main innovators. After meeting in 1907 Braque and Picasso in particular began working on the development of Cubism in 1908. Both artists produced paintings of neutralized color and complex patterns of faceted form, now called Analytic Cubism. In 1912, they began to experiment with collage and papier collé.
Their productive collaboration continued until 1914, they worked closely together until the outbreak of World War I in 1914 when Braque enlisted in the French Army, leaving Paris to fight in the First World War.
French art critic Louis Vauxcelles first used the term Cubism, or "bizarre cubiques", in 1908 after seeing a picture by Braque. He described it as 'full of little cubes', after which the term quickly gained wide use although the two creators did not initially adopt it. Art historian Ernst Gombrich described cubism as "the most radical attempt to stamp out ambiguity and to enforce one reading of the picture - that of a man-made construction, a colored canvas". The Cubist movement spread quickly throughout Paris and Europe.