The Saar Offensive begins

On 7 September 1939, four days after declaring war on Germany, French troops crossed the Reich border at several points in the Saar and occupied the first villages, abandoned by their inhabitants. So began the operation that the French called the “offensive on behalf of Poland” and that history remembers as the Saar Offensive. Through it the commander-in-chief of the French army, General Maurice Gamelin, was to keep the promise made to Poland in May 1939: to draw westwards part of the German forces that had for a week been smashing the Polish Army. In chronicles of the war the day is a symbolic date. The operation itself got under way slowly and hesitantly, and from the start its scale was far more modest than had been imagined in Warsaw.

The promise of May 1939

France was bound to Poland by the alliance of 1921. After the Germans seized Prague and after the British guarantee to Poland, the general staffs of the two countries sat down to talks. On 19 May 1939 in Paris, Gamelin and the Polish minister of military affairs, General Tadeusz Kasprzycki, signed a protocol under which, in the event of a German attack on Poland, France undertook to begin air operations at once, to launch offensive actions with limited objectives from the third day of mobilisation, and, once Germany’s main effort was directed against Poland, to mount an offensive “with the bulk of its forces” no later than the fifteenth day of mobilisation. Formally the protocol was linked to a political agreement which the foreign minister, Georges Bonnet, signed with Ambassador Juliusz Łukasiewicz only on 4 September, when the war had already begun. The Polish command nevertheless built its calculations on these provisions: the operational plan “West” assumed that the army would hold out for the first weeks until the French attack got moving in the west.

The wording of the protocol, however, was more elastic than Warsaw believed. In French military terminology “the bulk of its forces” meant a detached part of the army of unspecified size, and no provision mentioned an assault on the Siegfried Line. French operational instructions of May and July 1939, known neither to the Poles nor to the British, envisaged in the first phase only an approach to the German fortified position between the Moselle and the Rhine and “strictly limited” operations against its forward elements. An attempt to attack on a broader front, east of Saarbrücken, was treated merely as one possibility. According to the Polish historian Wojciech Mazur, who has studied Gamelin’s attitude towards Poland, from the spring of 1939 the general sought to reduce French commitments to a minimum without at the same time alienating the ally.

General mobilisation in France began on 2 September. The third day of mobilisation therefore fell on 4 September, and the fifteenth on 16 September.

The first days of war on the border

In the first days of September the Franco-German border was strikingly quiet. In Directive No. 1 of 31 August, Adolf Hitler ordered that in the west the initiative in opening hostilities be left to the British and French, and that minor border violations be repelled only locally. French troops manned the Maginot Line and completed their concentration, while the air force flew cautious reconnaissance missions.

Gamelin had no intention of hurrying. On 2 September, speaking at the War Ministry with Feliks Frankowski, counsellor of the Polish embassy, he is said to have stated plainly that he had no right to sacrifice 200,000 men in an attack on the German fortifications, but that “in nine days” he would carry out a manoeuvre that would force the Germans to withdraw some of their forces from Poland. On 4 September, in notes for his staff, he announced a land operation “between the Rhine and the Moselle” intended to “draw towards us the maximum of German forces”, and that evening, at the Château de Vincennes, he told visiting British officers that he had resisted pressure to move immediately and intended to proceed slowly and methodically, treating the operation as a test of his own strength and the enemy’s. Group Captain John Slessor, who was present, noted that the Frenchman “regards this offensive as little more than a gesture”. At the same time telegrams were going to Warsaw with assurances that the land operation would begin any day.

During the night of 5–6 September the first French reconnaissance patrols moved onto the German side. They penetrated a few hundred metres and met no enemy. On 6 September the commander of the North-Eastern Front, General Alphonse Georges, issued an instruction on the operation to the 2nd Army Group. During the night of 6–7 September reconnaissance units, especially in the sector of the 3rd Army, pushed deeper and reached border villages from which the Germans had earlier evacuated the population. The first minor skirmishes took place.

7 September

On 7 September the French crossed the border on a wider front, around Saarbrücken and the valley of the Blies. The operation was conducted by General André-Gaston Prételat’s 2nd Army Group, made up of the 3rd Army (west of the Saar, around the Warndt Forest), the 4th Army (between the Saar and the Blies) and the 5th Army (further east, towards the Palatinate Forest). Most chronologies give this day as the start of the offensive. Researchers working from the French archives point out, however, that the main attack, in line with Prételat’s instruction, began only at dawn on 9 September, and that on 7 and 8 September it was mainly reconnaissance and leading units that went into action.

The number of troops involved depends on how one counts. Chronologies usually speak of ten divisions, and some accounts of eleven or twelve, advancing on a front of about 25–32 kilometres. Ten active divisions was, moreover, the figure Gamelin himself used when arguing that he had fulfilled his obligation to Poland. In reality the burden of the fighting rested on a few divisions, mainly of the 4th Army, which often went into action with only part of their strength, straight from the trains, without full equipment and without reconnaissance of the German defences. Most of the soldiers were freshly mobilised reservists. The infantry did not know how to co-operate with the tanks attached to it, and bad weather limited air support.

The empty belt before the Siegfried Line

The French entered a zone that the Germans had prepared for just such an eventuality. The border belt in front of the Siegfried Line, the so-called red zone, had been cleared of its inhabitants before the war or in its first days. Sappers blew up the bridges over the Saar and the Blies, and mined the roads, paths, bridges and abandoned houses with thousands of anti-tank and anti-personnel mines, including the new “bouncing” S-mines, which sprang out of the ground and sprayed fragments at head height. The soldiers of the German 1st Army under General Erwin von Witzleben, part of General Wilhelm von Leeb’s Army Group C, were under orders not to counter-attack and to confine themselves to skirmishing, shelling and delaying actions. In the forefield the defence was conducted mainly by covering units, among them elements of the 6th Infantry Division.

It was the mines, not the German infantry, that were the main enemy of the French. The very first reconnaissance groups suffered losses on them, and the first French R35 tanks were blown up in the minefields near Bliesbrück. The columns advanced methodically, step by step, behind sappers clearing the roads. Even so, progress was visible: the French took most of the Warndt Forest west of Saarbrücken and a dozen or so abandoned German villages, among them Gersheim, Medelsheim and Kleinblittersdorf. At their furthest they reached a depth of about 8 kilometres, still short of the main position of the Siegfried Line.

What each side saw

The forces the Germans had in the west at this time were weak. Almost the entire air force and all the panzer divisions were fighting in Poland. In the west stood mostly reserve divisions of the second and third waves, poorly armed and lacking cohesion, and the Siegfried Line was unfinished in many places. At Nuremberg after the war Alfred Jodl spoke of 23 German divisions facing some 110 French and British ones; other calculations, which also include fortress units and reserve formations still being raised, give slightly more than 30. French intelligence judged correctly that the Germans were relatively weak in the west. The French command, however, reckoned above all with the fact that it had no heavy artillery capable of breaking concrete bunkers, that an offensive through the Saar led down a narrow corridor between Luxembourg and the Rhine, and that any outflanking move through Belgium was ruled out by Belgian neutrality. It also feared retaliatory Luftwaffe raids on French cities and factories.

On the German side the French entry into the Saar was received with unease but without panic. It was remembered that in 1914 initial successes had been followed by defeat on the Marne, and it was known how thin the screen on the western border was. Yet the German command did not transfer a single division from Poland to the west. It soon turned out that it did not need to.

In Poland news of the attack in the Saar was greeted with hope. Radio and press announced that the French had entered Germany, and the Polish command waited for reports of German troops being withdrawn from the eastern front. Meanwhile the battle for Warsaw and the Vistula line was already under way in Poland: the Germans had entered Kraków on 6 September, the Commander-in-Chief, Marshal Edward Rydz-Śmigły, had left the capital during the night of 6–7 September, and the defence of Westerplatte ended on that same 7 September with the surrender of the garrison.

Place in the war

The Saar Offensive was the only significant land operation by the Western Allies in the whole of 1939. Conceived from the start as an armed demonstration rather than a breakthrough, it could not change Poland’s fate. As early as 12 September Gamelin ordered the advance halted in front of the Siegfried Line, and on the same day the prime ministers of France and Britain, Édouard Daladier and Neville Chamberlain, meeting at the Supreme War Council in Abbeville, endorsed the decision not to undertake a large-scale offensive in the west. After the Soviet invasion of Poland on 17 September and the fall of Warsaw, Gamelin ordered on 21 September that the troops be withdrawn to their starting positions. In mid-October the Germans, reinforced by divisions transferred from Poland, counter-attacked, and on 16–17 October the last French covering units left Reich territory. Counting killed, wounded, missing and sick, the French lost some 2,000 men in the operation.

Whether a determined attack in September 1939 could have changed the course of the war remains one of the most debated “what ifs” of the entire conflict. German generals such as Jodl and Siegfried Westphal claimed after the war that the western front would have held for a week or two at most. Some historians, especially Polish ones, see the halting of the offensive as a breach of an allied obligation. Others, including many French historians, stress that with the doctrine, weaponry and pace of mobilisation of the day, the French army was incapable of quickly breaking through the German fortifications before Poland fell. One thing is certain: after a few days of cautious advance, a silence descended on the west that came to be called the Phoney War. It lasted until 10 May 1940, when Germany itself struck at France.