In the late fifties, Citroën's model line up comprised the 2 CV and the D Series, the former being designed to cater for the bottom end of the market and the latter aimed at the upper echelons. There was a yawning chasm between these two extremes and the company undertook a number of design studies including the Cocinelle and the C-60 in an attempt to plug the gap. 

The rise of the middle classes throughout Europe created a demand for a more luxurious,stylish and faster car than the 2 CV while remaining economical to run - the company had hoped the ID 19 would fill this role.

In 1959, Pierre Bercot laid down the design brief: - a large boot and seating for five in a car that must be no longer than four metres and no hatchback.  This latter restriction meant that Bertoni was obliged to create a classic three box design and in order to provide sufficient room for the rear passengers, he was obliged to use the reverse slope rear screen that had been pioneered in Europe by Ford of Great Britain with their Anglia.

A number of different engines were considered - a flat four comprising two 2CV units with a displacement of about 950 cm3, the 610 cm3 flat twin developed by Panhard, or to develop a larger capacity version of the flat twin from the 2CV.  It was felt that using the Panhard flat twin would result in the new car competing with the Panhard 24 which was under development.  By this time, Panhard was being run by Citroën.  The decision was taken to use an enlarged version of the 2CV engine and for the 24 to be a two door car only.

Due to budgetary constraints, the decision was taken to develop the 2 CV - a new 602 cc engine and a new, much less utilitarian body but fitted to the 2CV chassis and employing that car's interconnected suspension.  Flaminio Bertoni came up with the design that he later described as his favourite.

However, the Service des Mines (the French automobile regulatory authority) insisted that the lights be raised due to concerns about how well they would illuminate the road and as a result, they were elevated and the front wings were redesigned to accomodate them. 

The bonnet was also redesigned to incorporate the 'aesthetically challenged' dip that gave the car so much of its character.

French magazine l'Auto Journal came up with a not dissimilar rendition (above), albeit with an air intake.

Neither magazine envisaged either the rectangular headlights or the dip in the bonnet that were revealed in the production models

Below, the Anglia from the British Ford Motor Company was the first European car to feature the reverse slope rear screen.