The Dyane was intended to replace the 2CV... but the Tin Snail was too much of a survivor. So this upgraded and restyled 2CV went on sale alongside the model it was designed to supersede. The chassis was the same with a 425cc flat-twin engine on the 4 and a 602cc powerhouse on the 6, and the more angular looks were still closely 2CV-related, even down to the full-length canvas sunroof. It was clearly an update of the original design, with the addition of a hatchback. It was dropped five years before the car it was meant to oust.
info from Octane