Did you know that hydropneumatic suspension was tested on non-Citroën cars in the 80s?
Volvo was testing it in a modified 740 model where under the hood, hydraulic struts were fitted in place of the stock MacPherson struts.
Tribute to Citroën Hydropneumatic Suspension
This video shows a visual history of the development of hydropneumatic suspension in various Citroën models.