André Citroën built armaments for France during World War I and after the war he had a factory and no product. In 1919, the business started to produce automobiles, beginning with the conventional type A. The Type A was designed by Jules Salomon, Chief Design Officer from Le Zèbre.
Citroën was a keen marketer—he used the Eiffel Tower as the world's largest advertising sign, as recorded in the Guinness Book of Records. He also sponsored expeditions in Asia (Croisière Jaune) and Africa (Croisière Noire), intended to demonstrate the potential for motor vehicles equipped with the Kégresse track system to cross inhospitable regions. The expeditions conveyed scientists and journalists.
In 1924, Citroën began a business relationship with American engineer Edward G. Budd. From 1899, Budd had worked to develop stainless steel bodies for railroad cars, for the Pullman in particular. Budd went on to manufacture steel bodies for many automakers, Dodge being his first big auto client. In 1928, Citroën introduced the first all-steel body in Europe.
The cars were initially successful in the marketplace, but soon competitors (who were still using a wooden structure for their bodies), introduced new body designs. Citroën did not redesign the bodies of his cars. Citroëns still sold in large quantities in spite of not changing the body design, but the car's low price was the main selling point and Citroën experienced heavy losses.
In an attempt to remedy the situation, Citroën developed the Traction Avant. The Traction Avant had three revolutionary features: a unitary body with no separate frame, front wheel independent suspension, and front wheel drive. Citroën commissioned Budd to create a prototype, which evolved into the 7 horsepower (CV), 32hp (24kW) Traction Avant of 1934.
In 1933, Citroën also introduced the Rosalie, a passenger car with the world’s first commercially available diesel engine developed with Harry Ricardo.