As one of the first large scale Allied offensives of the war, the first battle of Champagne proved a stern test of tactics from which the French would have to learn. To capitalize on the strategically vulnerable position of the Noyon salient, the furthest extent of German progress into France, French commander Joseph Joffre was tasked with directing the French 4th Army against the German 3rd Army. The initial French attack on 20 December was blocked robustly by the German line, which had a major defensive advantage from strategically placed machine gun units. Throughout December and January successive waves of French attacks in the area between XXVI Corps and the Colonial Corps were met by German counterattacks. The French gained little useful ground by the time the offensive was called off in March 1915, and are estimated to have sustained at least double the 40,000 total casualties of the Germans.