From 14-16 June 1940, three German corps (seven infantry divisions) of the German 1st Army attacked five entrenched fortress machine gun regiments of the French XX Army Corps in the Sarre region.  For the offensive, the 1st Army massed about 1,000 artillery pieces in the largest artillery concentration of the French campaign.  The French regiments stubbornly resisted and after one day of hard combat, the 1st Army’s commander, Generaloberst von Witzleben considered ending the offensive.  However, the French withdrew, leaving only a small rear guard, and the Germans broke through the fortification zone, splitting the Maginot Line into two parts.

The fighting more resembled a World War I battle that the blitzkrieg that was going on elsewhere in France.  Combat was intense, leaving large areas of the Saar region heavily damaged.  After two days of combat, more than 1,000 German and French soldiers lay dead on the battlefield.

"...my own part in this campaign was limited to the fighting in Lorraine, where I served as chief of staff (Ia) of the 197th Infantry Division. It formed part of the First German Army which on 14 June attacked the famous Maginot Line at Puttlingen, south of Saarbrucken.  I had a good opportunity of seeing the battle at first hand, although in our division only the artillery and an engineer battalion were engaged in the actual breakthrough.

The Maginot Line was widely believed to be impregnable, and for all I know there may still be those who think that the fortifications could have resisted any attack.  It may be of interest to point out that the Maginot defenses were breached in a few hours by a normal infantry attack, without any tank support whatever.  The German infantry advanced under cover of a heavy air and artillery bombardment in which lavish use was made of smoke shell.  They soon found that many of the French strong points were not proof against shells or bombs, and moreover, a large number of positions had not been sited for all around defense and were easy to attack from the blind side with grenades and flamethrowers.  The Maginot Line lacked depth, and taken as a whole the position was far inferior to many defensive systems developed later in the war.  In modern war it is in any case unsound to rely on static defense, but as far as the Maginot Line was concerned the fortifications had only a moderate local value."

Major General F.W. von Mellinthin, Panzer Battles:  A Study of the Employment of Armor in the Second World War,  (University of Oklahoma Press, 1956)