Although Vincent and Theo had discussed the future possibility of living together in Paris, Theo's answers had been somewhat vague and evasive, prompting a desperate, exhausted, and sick Vincent to arrive in Paris unannounced in March 1886. He sent a letter to Theo by messenger apologizing for the surprise and telling Theo to meet him at the Louvre. In June the brothers moved in together, renting a spacious apartment with a studio in Montmartre. In April 1886 Vincent began working in the studio of the painter Fernand Cormon as he had intended to do when in Antwerp, and this apprenticeship allowed him to meet the painters John Russell, Louis Antequin, Henri de Toulouse-Lautrec, and Emile Bernard, who became one of Vincent's dearest friends. Goupil and Company having been dissolved, Theo had begun to work for the firm's successor, Boussod, Valadon, and Company. Through Theo's work selling Barbizon School Realist and Impressionist work, Vincent was able to see the avant-garde painting about which he had heard so much, and he even had the opportunity to meet many members of the central Impressionist circle of Paris, including Monet, Degas, Renoir, Sisley, Pissarro, and Aragon. In May, Vincent saw the eighth Impressionist exhibit, where he was struck especially by the Symbolist work of Gauguin and Seurat's neo-Impressionism, also known as Pointillism. Although he was still an outsider because of his non-French nationality, his unallied work, and his unpredictable bipolarity (which sometimes made him seem extremely argumentative and eccentric), Vincent finally felt part of a community of artists. He was able to trade paintings with many of the Impressionists, and a Parisian dealer even took some of his work. However, he was still unable to sell any work for money.
The influence of the Impressionists' color theories and use of light, along with his rising interest in Japanese prints, brought Vincent closer to his mature style as he tried a pseudo-Pointillist approach to painting in discreet, regular, short brushstrokes in heavy impasto and explored vibrant color, "seeking oppositions... to harmonize brutal extremes... trying to render intense color and not a gray harmony" (L 470). By August 1886, Vincent had left Cormon's studio because of Cormon's refusal of the new color theories and his insistence on painting plaster casts rather than live nude models. Vincent painted atmospheric cityscapes (like View from Vincent's Window and The Roofs of Paris) and a remarkable series of flowers in vases (like Vase with Poppies, Daisies, Cornflowers, and Peonies and Vase with Gladioli) to discipline his discovery of powerful color and Impressionist/neo-Impressionist theory. His Paris style is a unique amalgam of Impressionism and his own mature style of proto-Expressionism; van Gogh was influenced by Impressionism and the flattened, linear forms of Japanese prints (which he collected), but also by the old Dutch masters. His art was inherently synthetic, combining disparate influences to create a completely unique vision and style of stylized representation that went far beyond the circumscribed confines of Impressionism. He began to distort and exaggerate form to express the overwhelming turmoil of his emotional life.
By January 1887, Vincent had become closer to Bernard and the rest of the Paris avant-garde through time spent at the art shop of Pere Tanguy, which served as an informal avant-garde headquarters. He began to concentrate on still-lives (like A Plate with Lemons and a Carafe and the famous Still Life of Shoes) and portraits and self-portraits, which occupied him throughout the rest of his time in Paris. The progression of his style is extraordinary, from his 1886 Self-Portrait in a Dark Gray Felt Hay and Portrait of a Man with a Skullcap, through his winter 1886–87 Self-Portrait as an Artist and Portrait of Pere Tanguy, to his incredible Woman at a Table in the Cafe du Tambourin, Self-Portrait in a Straw Hat, and Portrait of Pere Tanguy, painted in the spring and summer of 1887 and the following winter. His idiosyncratic sense of patterned brushstrokes, thick textures, vibrant and unnatural, even acidic color, and distorted, flat forms alter "the reality of things" and "natural laws" to achieve profound emotional ends, "to touch people...by expressing deep and profound emotions" (L 218).
In Paris, Vincent's psychiatric health began its decline, and the dark side of his complicated condition (probably a combination of mild epilepsy and schizophrenia or bipolar disorder, compounded with syphilis, glaucoma, Digitalis poisoning from paint, and a weakness for absinthe and alcohol) started to reveal itself in violent mood swings, depression, and drunken and erratic behavior. Theo wrote to his sister Wil that "it seems as if there are two different beings in him, the one marvelously gifted, fine and delicate, the other selfish and heartless" (Hulsker 248). In the winter of 1887, Vincent became romantically involved with the female owner of the local Cafe du Tambourin, where he exhibited work with rising post-Impressionist stars like Gauguin, Toulouse- Lautrec, and Bernard–he was even able to organize his own exhibition of Japanese prints at the cafe in March of 1887. That spring, Vincent spent considerable time painting, walking, and talking with his new artist friends, especially the neo-Impressionist Paul Signac and Bernard, and his affair with the cafe proprietress ended after about five months.
By the beginning of 1888, Vincent had managed to exhibit his own work at two substantial, proper shows–one that he organized himself in November 1887 at a restaurant to display the work of the circle of the younger Paris Impressionists, who became known temporarily as the "Impressionists of the Petit Boulevard." The neo-Impressionist leader Georges Seurat was impressed by the show, as was Paul Gauguin (both artists who had influenced Vincent when he saw their work in Paris), and Vincent was able to show some work with Seurat and Signac at the Salle de repitition of the Theatre Libre d'Antoine. In February 1888, after experiencing a near physical and mental breakdown due to stress and alcohol, "seriously sick at heart and in body and nearly an alcoholic...without the courage to hope" (L 544a), Vincent decided he must move to Arles, in the south of France, where he could work in a more temperate climate more quietly and independently and with fewer expenses. He intended to return to bucolic landscapes, open-air light and color, and peasant portraiture, writing to his sister Wil, "the thing I hope to achieve is to paint a good portrait" (LW 1). He decorated Theo's apartment with Japanese prints and his own paintings and then left his brother (whose health was in decline due to syphilis) and artist friends in Paris on February 18, 1888.