After the return to Milan the corps was given the task to defend Italy along the Swiss-Italian border. To aid in its task the corps was given command of the Alpine Wall fortifications in its area of operation. When Italy declared war on France on 10 June 1940 the corps was near the French-Italian border in Limone Piemonte. The Italian Army only performed limited patrols and remained in its positions until "after" France had asked for an armistice on 20 June 1940. The next day the Italian divisions crossed the border in force, but stiff French resistance stopped them along the entire front after a few kilometres. During the campaign the corps commanded the 3rd Mountain Infantry Division "Ravenna", 6th Infantry Division "Cuneo" and a mixed unit of four Alpini and two Mountain Artillery battalions.