The year 1955 saw the introduction of the DS, which was the first model to introduce the now famous hydropneumatic Suspension system, which had been tested on the rear suspension of the latest Traction models.

The DS was the first mass-produced car with disc brakes.

The DS featured power steering, an improved braking system, and hydropneumatic suspension.

From 1968 it also included directional headlights, operated by a hydraulic device (current models such as the Citroën C4 and C5 come equipped with this system, now digital, but still a major technological asset of the brand).

A high-pressure system was used to activate pistons located in the gearbox used to switch between gears and operate the clutch in the so-called 'Citromatic,' Citroën's version of a semi-automatic gearbox.

This high-pressure hydraulic system would form the basis of many Citroëns, including the SM, GS, CX, BX, XM, Xantia, and C5.