The Canon de 75 mle GPIII was a field gun used by Belgium during World War II. Cockerill mounted a sleeve in the barrels of ex-German 7.7 cm FK 16 guns received as reparations after World War I to convert them to the standard Belgian 75mm ammunition. After 1940, the Wehrmacht designated captured guns as the 7.5 cm FK 236(b). This gun was nearly the equivalent of the German 7.5 cm FK 16 nA and apparently saw wider service than the other captured Belgian guns.
Chamberlain, Peter & Gander, Terry. Light and Medium Field Artillery. New York: Arco, 1975
Gander, Terry and Chamberlain, Peter. Weapons of the Third Reich: An Encyclopedic Survey of All Small Arms, Artillery and Special Weapons of the German Land Forces 1939-1945. New York: Doubleday, 1979 ISBN 0-385-15090-3