Army Group 3 (Groupe d'Armées 3 [GA 3]) was a French Army formation during the Second World War, stationed along the river Rhine manning the Maginot line.
It was responsible for manning the southern end of the Maginot Line, along the River Rhine and controlled one army.
The army group's Commander-in-Chief was Général d'Armée Antoine-Marie-Benoit Besson.
Until 16 March 1940, the Altkirch sector was part of the Fortified Region of Belfort.
[1] At the midpoint of the Battle of France on 1 June 1940, the fortress troops of the SF Altkirch amounted to two fortress infantry regiments in five battalions, comprising 165 officers and 3,300 men.