Battle of Béthune French heavy artillery 75 gun badge

A scarce original First World War period French made battle brooch, in the form of a gold plated oval surround inscribed 'BETHUNE 1914 -15 -16' mounted with a French heavy artillery 75 gun, the reverse inscribed with embossed lettering 'LE CAUCHEMAR DES BOCHES' (The Nightmare of the Boches). Very good condition, complete with original pin fittings, minimal wear. Height 24mm. Width 31mm.