It consisted of 5600 long-term fortification, 70 bunkers, 500 artillery and infantry units, 500 casemates and bunkers and observation posts.
The French assumed that the Germans would act the same as in 1914 - will try to make a round of French troops through Belgium to the northeast. So their plan for the defense intended to reflect the German attack on the River Dyle and passive defenses in the fortified Maginot Line.
For the construction of the Maginot Line was spent around 3 billion francs ($ 1 billion in the prices of those years). The total number of troops on the line reached 300 thousand people. In multi-level underground forts were equipped with living quarters for personnel, power, powerful ventilation systems, narrow-gauge railways, telephone exchanges, hospitals, rest rooms, out of reach for the shells and bombs. In the upper ground floor housed elevators equipped with gun casemates. They were dug in the ground a concrete "box" with thick walls and ceiling of 3,5-4 meters. Top-performing cupola turret. Before the first line of defense had been dug antitank ditches, and exposed to anti-barrage of sea urchins. For the first line of defense settled down a network of reference points - the concrete pads for the infantry, artillery, searchlights, etc. At these points at a depth of about 50 meters under the ground were ammunition depots and equipment, equipped with elevators. Still further accommodated position of long-range heavy guns on the railway track. Was also upgraded the old defensive line consisting of the forts Belfort, Epinal, Verdi, etc. The depth of Defense Maginot Line was 90-100 km. French military planners considered impregnable Maginot Line. After entering the German troops in Poland in 1939 France and Britain decided that quickly help Poland, they have no will, and instead began planning for the long war. In early September, France hesitantly moved her troops in the Saar region, but on October 4, after the defeat of Poland, once again brought them over the Maginot Line (so-called Strange War). In 1940, German troops promptly walked her from the north through the Ardennes. After the capitulation of the French garrison surrendered to the Maginot Line.