From 1919, Clemenceau evokes to Marshal Petain then French
army commander-in-chief, the necessity to fortify borders of France. During
several years, studies follow each other, opinions are divided between the French
government and the army. Paul Painleve, War Minister from 1925 to 1929, decides
to drive defense policy toward a merely defensive strategy and nominates a commission,
the Border Defense Commission (in French CDF) in charge of studying possibilities
to defend borders. His successor Andre Maginot, supports the law relative to
the organization of borders defenses.
Genesis & construction
In 1930, the Senate votes the "Maginot law"
that permits the assignment of 2.9 billions French Francs (FF) to the construction
of fortifications established along the German and the Italian borders.
Credits only represent 5 or 6 % of the yearly budget of the army and are derisory compared to sum that it would be necessary to hire in order to mechanize the army for example. About half the credits are dedicated to the defense of the Lorraine area, key of arch of the defensive system, whereas only 50 millions FF are granted to the defense of the North of France. The Commission for Organization of Walled Region (in French CORF) created in 1927, is charged to select sites and to achieve plans of fortresses while the army's Engineers supervise yards. Projects ordered in 1929 during an economical pomp period are very ambitious. Fortifications established on a depth of half to one mile must create an uninterrupted fire line from Montmedy city to the Swiss border in the North and from the Swiss border to the Mediterranean sea in the South. The frame of the line is composed of powerful artillery works built every 4 miles which can do immediate shootings in order to stop any hostile penetration. In the space between artillery works, small works endowed with infantry weapons (machine guns and small caliber cannons) and stand-alone machine gun blockhouses assure the fire line continuity. The device is reinforced by networks of trenches, shelters, troops anti-tank and troops defences. In case of an enemy attack, a work or a blockhouse can be covered by the artillery of 4 main works (2 on the right, 2 on the left). The quick parts of artillery and infantry works (barracks, headquarters, ammunition rooms) are buried deeply in the ground. Only blocks with machine guns, cannons and mortars under concrete or under withdrawed steal turrets stand out. Behind the defense line, around work entrances, surface or underground concrete shelters are used by infantry platoons affected to the defense of space between forts.
Builder's yards are separated in two distinct phases, the second phase realization being tributary of a new budget assignment. First phase works, confided in civil enterprises, start from 1929. But an economic crisis context helping, overtakings of work credits under construction drag many postponements in the initial projects. So many constructions foreseen initially in the first phase of builder's yards are reprogrammed in the second one that will never be achieved. And due to a lack of credits, the model of defense proposed by the Commission also called "CORF front" is only applied in three walled regions : Metz, the Lauter and Upper Alsace areas. The walled region of Metz is the most powerful, composed of 11 artillery works and 7 infantry works for a length of 27 miles. The walled system is weaker in other sectors. Like the impassable well-known Ardenne forest, the North and the Rhine river areas are only fortified with light fortifications without artillery.
If the weakness of the Maginot line defenses along the Belgian border is the consequence of the revision to decrease of the initial fortification projects, it is also justified by the French defensive strategy. Indeed, Belgium allied country, has its own fortifications established along Albert canal as Eben-Emael fort. Besides, in case of conflict with Germany, the French military staff plans to preventively deploy its best mechanized forces in Belgium (the mobile wing of the French device). The importance of fortifications along of the German border (static wing of the French device) should dissuade all adversary attack through this area. Germans would be forced to get round the line by going through Belgium or Switzerland. The relief of Switzerland itself isn't proper for invasions, so only the hypothesis of the invasion of Belgium is kept in mind. And the decisive confrontation of a future conflict between France and Germany would take place in Belgium, putting the French territory to the shelter of destructions...
In the Alps, the context is different. The border with Italy didn't vary since the end of the XIXth century. Many fortifications already exist along this border. These are reused, modernized and integrated into the Alps Maginot line. The addition of artillery and infantry works permits to reinforce the existing. Over there, the relief formed of impassable massifs is naturally suitable for defense and fortifications are not as dense as in the Northeast. Thus, in the Alps defenses are especially localized around the practicable passage points by an invasion army and to the South of the device on the more permeable inshore part. Indeed, since the arrival to the power of Mussolini in 1922, the south of France is not to the shelter of a Italian attack anymore.
In 1934, Marshal Petain, War Minister, frees 1,2 billions FF, to finish works of the first incomplete phase. A part of this sum serves to pay loans (800 millions) contracted after overtakings of first works credits. The remains is affected to the creation of new works called "new fronts" works. That creates employments in the economic crisis context that touches France since 1932. Builder's yards will continue until 1940.
Some special units are created to form "the crew" of the Maginot line works : fortress troops. These troops wear special uniforms with their own attributes. Several regiments of fortress are permanent, they must be able to counter all surprised attack on behalf of Germany or Italy. In case of mobilization, thanks to the arrival of reservists, these regiments split themselves in 2 or 3 regiments and can complete works crews and "interval troops" which have to defend spaces between forts. Troops of fortress come from several weapons : the Infantry for fortress infantry regiments (in French RIF), the Artillery for position artillery regiments (RAP) and Engineers. In a work, the Engineers look after electricity, mechanics and transmissions. In the Alps, 7 alpine fortress light infantry battalions (in French BAF) assure with the Engineers and the Artillery the defense of fortifications. Each BAF owns a ski reconnaissance platoon (in French SES).
The Line, in case of conflict with Germany or Italy, must permit France to finish to mobilize all its reserves without fearing a sudden invasion of its territory through the German or the Italian border. But the geo-political context evolves quickly...
"The phony war"
In 1935, in violation of terms of Versailles Treaty, the military service is re-established in Germany. In 1936, Hitler remilitarizes the Rhineland, disarmed since the end of World War I. This action, doesn't make any reaction in the allied camp except the return of Belgium to neutrality. So in case of war with Germany, France can't preventively deploy its "mobile wing" in Belgium any more. This operation is now tributary of a German invasion in Belgium. In consequence, the defense of the Belgian border is decided and it will be achieved to the hurry with only light fortifications.
In France the general mobilization takes effect September 3, 1939, but many forts are already ready to fight since the end of August. The propaganda seizes of the walled line to make an impregnable rampart which will break any enemy assaults, maintaining thus in civil population, a wrong feeling of security. Since declaration of war, the French troops are in expectation.
During 8 months, nothing happens, except some artillery salvos shootings on the nearby German territory "to intimidate" the adversary. Only initiative of the French high command, the invasion of Saarland to honor his military support agreement with Poland invaded by Germans. This victorious offensive does a symbolic progression of 6 miles in Saarland evacuated by German troops before folding back "accomplished mission". In spite of the wait-and-see policy of the French army staff, the will to unpick enlivens crews, who create commando teams doing nightly offensive patrols in the no man's land that spreads between the French outposts and those of the Siegfried line the German equivalent of the Maginot line.
The creation of a Western second front, obsessive fear of the German high command, whereas most of its forces operates in Poland, won't achieve itself by reason of the lack of fighting spirit of the French Army staff.
The Polish question is solved at the end of September. Germans reorganize their troops and deploy them along the west border. May 10, 40, they invade Holland and Belgium. The English expeditionary corps and the best mechanized French units fly to the help of the Belgian army.
The German plan functions to perfection and May 13, 40, "panzers" penetrate in France by the Ardennes massif and jostle the French troops. German tanks make then a turning movement to the North Sea direction and charge at Boulogne and Calais. This encircling puts out of fight the elite of French forces and all the British expeditionary corps (l) that were advanced themselves carelessly in Belgium.
After the liquidation of Dunkerque's bag, the German army rushes southbound of France, piercing one by one all defense lines. So the French high command decides the evacuation of the Maginot line. Intervals troops must unhook June 15 followed the day after by forts crews. The first withdrawal takes place as foreseen June 15...
June 15, benefitting the situation, the German infantry does a breakthrough by doing a piercing in Saarland area doing its junction with troops which have penetrated in the French territory by Sedan one month before. The German troops occupy rears of the line, cutting all itinerary of retirement. Crews find surrounded. Alone, only delivered to themselves, they get ready to fight, ready for a honor baroud.
Works are attacked by their rears. Bombarded by the
German heavy artillery, some small works only endowed by light weapons
and no covered by big artillery works capitulate as the Welschhof and
the Haut-Poirier on June 21 and 24. The small work of la Ferte is also
occupied after the accidental death by asphyxia of all its crew. But no
work of the CORF fronts capitulates.
The Alps line : None shall pass!
Whereas a third of the French territory is already occupied by the German army, Mussolini declares war to France on June 10, 1940. The Duce groups 3 armies is 300 000 soldiers in the Alps along the French border. Facing this invasion army, French forces are reduced to minimum. With an initial effective of 550 000 men to the mobilization, the Army of the Alps account only 85 000 men in June 40 of which 42 000 fighters. Indeed since the beginning of the conflict, many mountain troops have been appropriated for Norway expedition of April 1940, then after May 40 to try to stop German invasion on the Northeast front. Prudent, Mussolini, doesn't attack. He prefers to let the German army defeat the French army and when the capitulation will be consumed, he will be able to grant for himself without fights a big part of the Southeast part of France. But Hitler has other intentions. Anxious to treat tactfully the adversary, so that France won't continue the struggle overseas with the United Kingdom, he globally refuses all territorial pretensions of the Duce. Italy will only occupy sectors that she will have conquered effectively at the moment of the conclusion of the armistice. Then Mussolini sees himself constrained to attack to insure some territorial possessions. And against the opinion of his staff, he orders an general offensive for June 21. The attack launches as planned, but in spite of the importance of italian strengths, the progression is stopped everywhere by the french resistance. Alpine mountain and fortress troops hold assaults by well adjusted salvos of artillery and automatic weapons. The very mobile and very adapted to the land SES stop all Italian infiltration attempts between works of the Maginot line. In the same way on June 22, a controlled offensive on Nice develops itself along the Mediterranean coastline. In this zone, fortifications are densest and Mussolin troops cannot go further Menton city. But at this time the Alps Army is attacked on its rears by the German army. Indeed, since June 21, 4 German divisions progress by the Rhone valley. The 22, Germans are blocked to doors of Chambery and June 24 the offensive directed to Grenoble is stopped at Voreppe. June 25, when the armistice takes effect, the Alps Army is still on its positions. In their fortified works, "remparts crayfishes" knew how to repulse with bravery all Italian attacks while on rears, under energetic chiefs conduct, the heterogeneous forces formed by alpine troops, senegalese skirmishers and navy troops contained the panzer rush.
During the war, the line of the Northeast is used by Germans to varied ends : test platform of new explosives like hollow charges, ammunition deposits or underground factories. Before the liberation, German troops entrench themselves in some works to delay the inexorable allied advance. After the war, from 1954 to 1958, in the settings of the NATO, the French army puts back most works in state of working, they will be operational until in years 60 and will be abandoned definitely in years 70. The Maginot line was an excellent instrument of fight allying fire strength and protection, while mobilizing a minimum of troops. This weapon was badly used by the French high command, that concentrated about thirty divisions behind it whereas sectors were completely empty as the Ardenne sector.
Troops of fortress proved their value however in June 40, but the situation was already without exit...
(1) Most the surrounded troops will be able to re-embark in Dunkerque, but
all the heavy material will be lost.
(2) In spite of Geneva conventions that stipulates that unbeaten troops cannot be taken to captivity.