How did Bonnard, one of the great masters of 20th-century painting, a secretive, anxious man with an ordinary everyday life, become this undisputed painter of intimacy, capable of transforming reality into a unique and incandescent world? Through his paintings, but also his private journals, his correspondence with Matisse and Vuillard, the photographs he loved, and the places where he lived, the film immerses us in the world of this master of color.