Peugeot created the Type 161 to reverse its financial woes following the First World War. It was a cheap, practical, very small economy car and was nicknamed the Quadrilette when shown at the 1920 Brussels Motor Show. It was available for sale in 1921. In order to put it into the minimal tax bracket (that of cyclecars, for whom the tax was 100 francs annually, the 4-cycle, 4-cylinder water-cooled engine displaced a mere 667 cc and produced 9.5 horsepower (7.1 kW). Taking advantage of this small power output was a very lightweight body, under 350 kilograms (770 lb). The vehicle's width was so diminutive that the two seats were placed in tandem, not side-by-side. Later in 1921, the Type 161E was introduced with side-by-side seats, the passenger seat slightly back to allow the driver room to operate the pedals. The car retailed for 9900 francs with top, acetylene lights, and spare tire, 9400 francs without. Fuel economy was highly impressive at 5.0 L/100 km (45 miles per US gallon or 56 miles per Imperial gallon). Top speed was 60 kilometres per hour (37 mph).
In 1923, modifications to the Quadrilette resulted in the Type 172. The track was widened so that the two seats could be placed abreast, improving comfort and space. Though the wheelbase was shortened, luggage room was more plentiful because there were no longer two rows of seats. The engine remained the same and weight was kept low. A special edition of the Type 172, known as the Type 172 BS or Quadrilette Grand Sport had an enlargened 720 cc engine with slightly more power.
Total figures for the Quadrilette amounted to 12,305 over three years, which was 31% of Peugeot's vehicle production for that time period. Confusingly, models of the Type 172 were attached both to the Quadrilette's nameplate and to that of its successor, the Peugeot 5CV. The Quadrilette and 5CV were sold side-by-side in 1924, after which Quadrilette production ceased.