The Wib 8 Simoun was designed around a 1925 specification from the Service Technique de l'Aéronautique (S.T.Aé, Technical Department of Aeronautics) for a two-seat fighter.

It was an all- metal machine, the structure mostly Duralumin and the covering narrow aluminium strips applied longitudinally.

There were cabane struts over the fuselage and a trailing edge cut-out in the wing over the pilot's cockpit to enhance his visibility.

A pair of synchronised 7.7 mm (0.303 in) Vickers machine guns fixed to the fuselage fired forwards through the propeller arc; in addition the rear cockpit was fitted with a pair of Lewis guns of the same calibre on a Scarff ring.

The fighter had a fixed conventional undercarriage with mainwheels on a split axle attached to the fuselage underside, supported by a pair of V-struts; there was a small tailskid.