The initial plan was to fit each ship with a director that fed data to the Mle 1923B electro-mechanical fire-control computer, but development was protracted and it was not ready in time for the first four ships. They were fitted with the simpler Mle 1919 type aviso mechanical computer; only "Léopard" and "Lynx" had the Mle 1923B computer upon completion. The earlier ships had their Mle 1919 computers replaced by the later computer beginning in 1927. Development of the director was abandoned and the ships were fitted with a Mle B.1926 coincidence rangefinder that fed data to the computers. This was replaced by a stereoscopic rangefinder in 1931 and by a PC.1936 model from 1937.