The Citroën DS 21 was a front-wheel drive saloon used in rallying during the 1960s, notable for its innovative self-levelling hydropneumatic suspension, which gave it outstanding stability on snow and uneven surfaces. Equipped with a 2.2-litre engine producing around 100–115 bhp, it was not the most powerful in its class, but it was one of the most effective in difficult conditions. Its greatest sporting achievement was victory at the 1966 Rallye Automobile de Monte-Carlo with Pauli Toivonen and Ensio Mikkander at the wheel, an edition that would go on to become controversial due to the disqualification of several factory entries over technical lighting regulations.