Sword bayonet for use with the 7.65 mm. M1889 Mauser rifle and carbine. The Gendarmerie bayonet blade is a T-back, rather than the flattened cruciform profile used on the regular M1916 bayonet.
These bayonets were produced at Manufacture D'Armes de le Etat (Arms Manufacturer of the State) in Liege, likely in the 1920s.