Due to the shape of its nose, the Morane-Saulnier Type N was aptly nicknamed the “Bullet”. Built in small numbers, it was the first French aircraft specifically developed as a fighter. Armed with a fixed, forward firing machine gun, its propeller was protected by the metal deflector plates pioneered by Roland Garros on the Morane-Saulnier Type L. Although it was faster and more maneuverable than previous aircraft, the Bullet was extremely difficult to fly and unpopular with pilots.
The Nieuport 10 biplane was originally designed for racing, this light plane was fast and relatively maneuverable. Its major design problems were its fragility, and its lack of a synchronized machine gun. Most were exported to Russia, Italy and Britian
The small Nieuport 11 biplane was affectionately known as the "Bébé" (baby). Originally designed for racing, this light plane was fast and extremely maneuverable. Its only major problem was in the design of its wing struts. In a steep dive, the struts allowed the wings to twist, sometimes with disastrous results. Used by the British and French to counter the Fokker E.III, the Nieuport 11 was disadvantaged by its lack of a synchronized machine gun.
This small fighter was designed and built in France, where a few were used as trainers. Belgium ordered 30 for frontline use, but its extremely poor control caused the order to be cut to 10, or perhaps as many as 18, and it is not thought that any were actually used operationally.
Apparently the prototype was flight-tested by a number of pilots, including Charles Nungesser, who flew the M.1 on 29 January 1916. During that flight the aircraft crashed and Nungesser broke both legs and his jaw. From what I read the Po.M.1 was not put into production for the French military, yet some M.1s were sent to the training schools. None however equipped operational units.
Thirty were ordered by Belgium because of their inability to recieve enough Nieuports. Discovering what the French already knew, these aircraft were modified by having the cone de penetration deleted, the tailplane and elevators enlarged, and a fixed fin fitted. Willy Coppens noted that the M.1 remained unstable even after these alterations and consequently the initial order of 30 was reduced to (approx.) 10, which I believe, were never used operationally.
Having an urgent need for new fighter aircraft the Belgian authorities ordered thirty Ponnier M.1's, although this machine was rejected by the French Armee de l'Air for being too dangerous to fly. Most Belgian pilots also refused to fly the Ponnier (of which only ten were delivered) and it was quickly withdrawn from use.