Dassault designed the Mirage F1 as a private venture, using its own funds, as a successor to its Mirage III and Mirage 5 fighters, with the F1 being a smaller version of the Mirage F2 being developed for the French Air Force.
In order to comply with the French Air Force's requirement for an all-weather interceptor, the first production Mirage F1C was equipped with a Thomson-CSF Cyrano IV monopulse radar.