André Citroën graduated  the Ecole Polytechnique in 1900 and by 1902 he had founded his first company.

He acquired a patent for a gear-cutting technique that he discovered in Poland, the  chevron-shaped teeth.  provided the inspiration for the double chevron, emblem of all vehicles produced by Citroen.

In 1907,  Citroen  was brought in to help Mors, a car manufacturer in Paris and thus began his association with the Automobile industry. 

When World War 1 broke out in 1914. Citroën joined an artillery regiment and was sent to the front, where he noted that a lack of munitions was forcing the French army to save shells. Having visited the Henry Ford plant in the USA in 1912,Citroën was familiar with the principles of work organisation. He believed that it would be possible to produce 10,000 shells daily.

In 1915,  he persuaded French authorities  to set up a shell factory. In 1917, the Javel plant came into operation. Built in just four months , the plant produced 50,000 parts daily .

As the war drew to an end,  Citroën turned his attention to converting his munitions plant into a car plant. Like Henry Ford, he decided to make a single  utalitarian model. Before the war, car buyers had bought a chassis without bodywork, mounted on wheels without tyres. Citroën starts a European revolution when he presents the Type A 10CV. Manufactured using volume production techniques, the Type A is delivered with a fully fitted body,  tyres, a spare wheel, two headlamps and an electric starter.

At the 1924 Paris Motor Show, Citroën unveiled the All-Steel B10, a car that revolutionises the industrial manufacture of bodywork. 

The production process was developed by the American company Budd, but US carmakers are too conservative and wary of adopting it because they considered it to be too modern. 

The floating-power engine, which is used around the world today, was developed in 1932 in the  USA . This simple idea  places the engine on rubber shims so that vibrations  to the chassis are minimised. The invention's merit was  recognised of Citroën, who bought the exclusive  European licence.

When in 1934 many cars were still built from a wooden structure covered with metal parts and fixed to a chassis, with the engine bolted on directly, wheels mounted on rigid axles with brakes operated by cables or rods. Citroën created the first recognisably modern volume production car. 

The  Traction Avant when launched had a steel monocoque body, an engine mounted on  Silentbloc and independent front and rear wheels. In addition it also had the as then rare  front wheel drive.

The technology proved to have some teething problems and Citroen who was an all or nothing kind of guy, had bet the whole shooting match on its success, but the world wasnt quite ready. facing Bankruptcy Citroen handed over control to Michelin 

André Citroën died on 3 July 1935, at the age of 57 without seeing his dreams for the Avant come to fruition. 

The company wa taken over by Pierre Michelin and Pierre Boulanger, After the death of André Citroën. , they continued to manage the Javel plant developing  and refining the Avant into the legendary car it became. They also embarked on some ambitious new development work.

Pierre Michelin died in an accident at the end of 1937.

 In 1939 the 2CV was scheduled to arrive on the market  , when war intervened once more

Citroen engineers secreted the 2CV for the duration  war.

After the war, the French government introduced strict planning measures. 

The rationing of raw materials delayed the launch of the 2CV until 1949

 Pierre Boulanger died in an accident in November 1950.

The 2CV though remained in production for the next 40 years.

Robert Puiseux, son-in-law of Edouard Michelin, took over  at Citroën and ordered the replacement of the ageing  Traction Avant.

The DS was unveiled at the Paris Motor Show in October 1955.

It was equipped with power assisted brakes with discs at the front, power steering and a semi-automatic gearbox. The constant height hydropneumatic suspension, first introduced on the rear axle of the last 15 Six,   are a challenge for contemporary mechanics, but  this  same system of hydropneumatic suspension  provides the basis for the  GS, CX, and BX, Xantia and XM and becomes the most recognisable citroen trademark....

In 1974, Citroen merged with Peugeot to form  the PSA Group.