When "Fall Gelb" began in May 1940, his troops saw action during the opening phase of the Battle of France during assaults on the Belgian fortress Eben-Emael, the Maas river and Albert Canal bridges. Koch's commandos successfully captured Fort Eben-Emael and the bridges in Veldwezelt and Vroenhoeven. Only the bridge at Kanne, which was blown up by the Belgian defenders, was not taken by the German paratroopers. For these successful operations, Walter Koch along with ten other "Wehrmacht" officers received the Knight's Cross of the Iron Cross.