Valentine Henriette Prax was born in 1897 in Bone (Annaba). Her father, Henry Prax, was a Catalan from Perpignan, who was established as a forester in this city, which is the second largest harbour in Algeria. He also served as vice-consul.

After three years spent studying in the School of Fine Arts of Algiers, Valentine Prax decides to sell some jewelry donated by her grandmother to finance her journey to France. She leaves her family, her country and arrived in Paris in 1919, barely adult. She moved into the workshop of 35 Rousselet street, where she begins to paint on porcelain and creates fashion designs. She quickly met with her neighbor of the second floor, the sculptor Zadkine, who introduces her to the avant-guarde artists of Montparnasse, in the small smokey and crowded coffees of the Rotunda at the Dome.

Valentine discovers the Cubists, the Fauves, Picasso, Braque and Van Dongen, the paintings of Cezanne, the personal collection of the art dealer Ambroise Vollard, reading Apollinaire and Max Jacob. She sets up her easel in Bièvres, in Clamart, in Montfort l'Amaury and in Marly-le-Roi and produced landscapes in grey harmonies, green and brown. Nevertheless, Valentine Prax did not painted from models but contemplates the world and transcribes it through a poetic prism.

The summer of 1920 Foujita and Fernande Barrey welcome Valentine in Collioure. She then receives a telegram of Zadkine "Come. Talk about marriage. "She immediately joined him in Bruniquel, a medieval town of Quercy that Zadkine adopted. They married on August 14, 1920. Valentine's parents made the trip. The Foujita are their witnesses.

After a first solo exhibition at the gallery Mouninou in April 1920, she exhibited for the first time at the Salon des Independants. In December 1921 Valentine Prax exhibited at the gallery La Licorne, led by the great collector Maurice Girardin. Art critics sees in her work "fresh spontaneity without embellishment", an "ingenuity that mocks ignorance." Zborowski, the merchant  of Modigliani, bought some of her paintings and opens an account for her in a colours shop - Valentine can continue to paint in peace. Her works were notices in the Salon d'Automne, in the International Exhibition of Arts in Düsseldorf (1922) and also in the Women Painters Exhibition (1923). In 1924 she exhibited at the Berthe Weil Gallery.

Two characteristics emerge from these first pictures: concern for the composition and sobriety. Valentine Prax established in total control the rhythmic cadences that govern the space of her paintings. They are built in large plans, with a geometric aspect. The design is specific, the tones are cold and the composition is tightened, clearly grouping the patterns. At that time, she hesitated between naive primitivism of Rousseau and the neo-realism of Charles Dufresne or Roger de la Fresnaye. From 1926 to 1931 her activity is prodigious. Each year she presents her works in one or more exhibitions. The young woman knows a real commercial success with her "reverse glass" - a technique once used by the popular image makers: presented through the glass, the color is very fresh, amazingly bright. In May 1926, she signed a contract with the Barbazanges Gallery which counts among its "protégés" Charles Dufresne and the sculptor Despiau. In Brussels several exhibitions are devoted to her work - in the Gallery Selection in 1922 in the Galerie Le Centaure in February 1927.

In 1928 Zadkine and Valentine left the Rousselet street, where they worked in very difficult conditions, for a more comfortable studio in 100 rue d'Assas.

When they do not occupy the Parisian workshop, the two artists are in their house in the Arques, acquired in September 1934. Somewhat dilapidated, the house has a barn and beautiful spaces where the couple creates four workshops. Valentine can finally paint at ease.

Valentine Prax is now a recognized name, personal exhibitions are devoted to her in London, Chicago, Philadelphia, at the Palais des Beaux-Arts in Brussels in December 1934. In Paris, she participated in the Salon d'Automne in 1933 and 1936, also in the Salon des Tuileries in 1935. On the occasion of the "international Exhibition of Art and technology in modern life" opened in May 1937, Valentine Prax was offered to paint one of the large glass roof of the Art museum modern, on the theme of Aviation.

The war strikes while Prax and Zadkine are in the Arques. Zadkine is working on a large Christ (1938/1940) in elm wood, settled today in the church of the village; Valentine has embarked on a project of tapestry drawings for the Legoueix Aubusson workshop but the  events rush and the tapestries will not be executed, despite the support of Jean Lurcat. Faced with the threat of war, Prax convinces Zadkine in extremis to embark for the United States but decided to stay herself to defend their works. The Parisian studio in the Rue d'Assas is forfeited. She saves Zadkine bronzes but rips her paintings off "rather than have them scattered under the Nazi boot." She endures hunger and the anguish of the Occupation in the complete solitude of her house in the Arques, enduring persecutions of the local militia. Painting is her only Viaticum - "this period of the war was the best for my artistic production," she confesses. She realizes La Fin des Temps Heureux, Arlequin dans la ferme dévastée, La Fin des temps Romantiques. The Rêveuse of 1945 marks a turning point in her work that turns to modern barocism. The lines undulate in the manner of snakes, contrasting with geometric constructions.

From that moment, the work of Valentine Prax will retain a pathetic worldview. The anxiety experienced during the years of war is always present in the mind of the artist and is reflected with startling force. In Paris, the Galerie de France successfully devotes an exhibition to her works in October 1942, however, she really found success after the end of the war -  she exhibited in the Faubourg Art Gallery in May 1950, at the Salon des Tuileries and the palace of Fine Arts in Bruxelles in 1951, in the Salon d'Automne of 1952.

In the late 50s, Valentine Prax finally finds peace and showed her interest in music in her paintings by depicting violins, guitars and other instruments, but she especially picture her inner music expressed through the singing of bright colors. She paints La Jeune et la Vieille Sorcière, Les Sorcières en transe, Les Naïades, which operate as a spell to restore peace and harmony, such as in La Paix Intérieure, that Valentine ended around 1960.

The year 1963 brings her the consecration of a major exhibition at the Galerie Katia Granoff, presenting together fifty paintings. From this period she paints many canvases on the theme of the see : Le Dernier Voilier (1960), Jeu Marin (1966), Les gens de la Mer (1966), Les gens Heureux or Le Jour Enchanté (1969-1970), Le Pauvre Pêcheur (1970), L’Enfant Heureux (around 1970).

When Zadkine died in 1967, Valentine Prax worked on the creation of a museum, in their workshop on rue d’Assas. The museum consists of a fund of about 300 works of Zadkine who wanted to donate them to the city of Paris. Valentine Prax continued to paint and to exhibit – in the Galerie Chappe-Lautier in Toulouse in 1968, in the Galerie René Drouet in Paris in 1968, 1971, 1973, in the Museum of Modern Art of the City of Paris in 1976. Encouraged by Jacques Lassaigne, Director the museum of modern Art of the City of Paris, she engages formalities to the City that accepts a donation in 1978 of a significant portion of her property. The following year, an exhibition on Zadkine at the City Hall mark the event. This donation is confirmed by the will of Prax in 1980, in which she donated to the City of Paris all of her belongings, on condition that the municipality creates a museum rue d'Assas. The 15th of April, 1981, Valentine Prax dies.