His parents, Omer and Leila Baldaccini, Italian of Tuscan origin, had a bar in Marseilles, where César was born in 1921 in the popular district of la Belle-de-Mai, at No. 71 rue Loubon, in the center. “I am basically an absolute autodidact,” he says. He first worked at his father’s, before attending in 1935 the courses of the School of Fine Arts in his hometown with his classmate Raymond Normand and, in 1943, the National School of Fine Arts in Paris with Michel Guino, Albert Féraud, Daniel David and Philippe Hiquily, like him in the studio of Marcel Gimond. He occupies a workshop in a former brothel of the “rue de l’Échaudé”, whose rooms, following the law Marthe Richard, had been awarded to students. He was a very talented person for the sculptures. From 1947, he worked plaster and iron. In 1952, at Trans-en-Provence, he made his first welding tests and his first sculptures in scrap, using inexpensive materials of recovery: his means are then always modest, thus for lack of money to afford marble, Caesar will recover in scrap dumps the materials of his first sculptures; tubes, bolts, screws, which become insects, or are found in the powerful curves of the Villetaneuse Venus. In 1954, he exhibited at the Lucien Durand Gallery and won the “collabo” prize for a sculpture entitled “Le Poisson” made in Villetaneuse; city ​​where he will work a dozen years, thanks to the help of a local industrialist, Léon Jacques. In 1956, he participated in the Venice Biennial; then in the São Paulo biennale and Documenta II in 1959. In 1961, he moved closer to Marino di Teana, and joined the group of New Realists, movement founded by art critic Pierre Restany, including Mimmo Rotella, Niki de Saint Phalle and Gerard Deschamps.