The 403 characterised the second model series after the War. Together with the 203, it deserved and earned a lot of credits in terms of reliability for Peugeot. The fenders were already fully integrated into the body, unlike for the 203. Pinin Farina was the author of the design, laying the foundation for a lasting relationship between Peugeot and Pinin Farina. The curved windscreen was introduced by him, too. It gives an aero dynamical advantage, and a larger space. The hatchback was replaced by a sedan, and a station wagon was re-introduced.

In line with reliability, conservatism was featured. This conservatism became especially evident when Citroen introduced its DS. French car producers offered a whole range of different cars. Interestingly, it was the conservatism that was successful in the long run, in this case. Peugeot did manage to make profits, Citroen not. In 1959, a new economical diesel engine supplemented the inner values of the Peugeot. Besides Germany, North-Africa developed as a new important market.