The design featured an innovative dual propulsion turbojet-ramjet configuration; the former being used to takeoff and attain sufficient speed to start the latter.

According to the Fédération Aéronautique Internationale, the aircraft held the flight airspeed record from 5 to 31 October of 1959, with a speed of 1,441.6 mph (2,320 km/h) attributed to Maj. André Turcat.

[1] Towed to the release point by SNCAC Martinet, Douglas DC-3 or SNCASE Languedoc transport aircraft, the glider provided valuable data for the design of the Gerfaut.

[2] To utilise this data SFECMAS's chief designer, Jean Galtier, initiated the 1400, 1500 and 1910 interceptor projects with delta wings and different types of propulsion systems.

The large tubular fuselage supported the same delta wing as used on the Gerfaut and the swept vertical stabilizer with rudder.

The forward fuselage had small triangular canards positioned at either side of this cockpit to counteract the center of pressure of the delta wing's tendency to depress the nose as the aircraft approached transonic speeds.

Despite this reported lack of power, the Griffon I still managed to attain a maximum speed of Mach 1.15 on its first supersonic flight on 11 January 1956.

At some point during its life the air intake was enlarged, probably when the more powerful Atar 101E engine was installed and before the aircraft attained its maximum speed of Mach 1.3 at an altitude of 8,560 m (28,080 ft).

Although the initial flight testing showed that engine performance above 9,144 m (30,000 ft) suffered, the aircraft's handling qualities were excellent.

Its nose gear collapsed on 19 June when Turcat was taxiing across a grass field and the aircraft did not fly again until 26 July.