The Saar Offensive was the French invasion of Saarland, Germany, in the first stages of World War II, from 7 to 16 September 1939. The original plans called for 40 divisions, and one armored division, three mechanised divisions, 78 artillery regiments and 40 tank battalions to assist Poland, which was then under invasion, by attacking Germany's neglected western front. Despite 30 divisions advancing to the border (and in some cases across it), the attack did not have the expected result. When the swift victory in Poland allowed Germany to reinforce its lines with homecoming troops, the offensive was halted. French forces then withdrew amid a German counter-offensive on 17 October.