Designed to meet the demands of a CAP (Chasse Armee Protection) 2 requirement formulated in 1919 by the newly-appointed Directeur de l'Aeronautique, General Duval, the Potez XI was a two-seater intended to fulfil bomber intercept and tactical reconnaissance at Army Corps level, and escort fighter tasks. The specification called for the use of a turbo-supercharged engine, and the Potez XI, which appeared in 1922, was powered by a 370hp Lorraine-Dietrich 12D water-cooled 12-cylinder engine equipped with a Rateau turbo-supercharger. Competing with the Hanriot HD.15, the Potez XI had a fabric-covered light alloy structure and was an equi-span two-bay biplane with over-hung ailerons on the lower wing. Armament comprised two fixed forward-firing 7.7mm machine guns and two similar weapons on a swivelling mount in the rear cockpit. The inadequacies of then-current steels to withstand prolonged operation of exhaust-driven turbo-superchargers led to cancellation of the CAP2 programme and development of the Potez XI was discontinued.