The Villiers XXIV had been the first French aircraft maker to use Handley Page slats and the Villiers 26 reconnaissance seaplane used a combination of automatically opening slats on the leading edge in front of the ailerons and another set which the pilot opened as he lowered the flaps.

[2] The Villiers 31 had a flat sided fuselage of rectangular cross-section behind the wing, built around a frame of chrome steel tubes and fabric covered.

[3] There was a 310 kW (420 hp) Gnome et Rhône 9Ab nine-cylinder radial engine in the nose, which some photographs show under a long-chord, close-fitting, circular cowling.

A curved, deep, balanced rudder, mounted on a small fin and slightly pointed on top, worked in elevator cut-outs.

The two mainwheels were mounted independently on V-struts from the lower fuselage with near-vertical oleo struts to the wing roots.