Saar Offensive

French Army Group 2, under General André-Gaston Prételat and deployed along the Lorraine front opposite Germany’s Saarland and Palatinate regions, completes its preparations for offensive operations after its formations are reinforced with mobilised reservists and conscripts.

Formed around the French Third, Fourth and Fifth Armies, Army Group 2 occupies the sector facing the German 1st Army under Generaloberst Erwin von Witzleben.

French reconnaissance patrols conduct preliminary incursions across the German frontier into the Saar, probing the thinly held German covering positions in front of the Westwall. German forces have orders to avoid a major engagement while the bulk of the Wehrmacht remains committed to the invasion of Poland.

The French Second Army Group launches Operation Saar, a limited advance into Germany intended to relieve pressure on Poland by forcing Germany to divert forces from the east. Eleven French divisions from the Third Army under General Charles Condé and Fourth Army under General Édouard Réquin take part in the offensive, advancing across the frontier on a front approximately 32 kilometres wide around Saarbrücken, with the main thrust led by the IX and XX Army Corps.

Opposing the French is General Erwin von Witzleben's German 1st Army, with 11 divisions covering a front of some 180 kilometres across the Saar and Palatinate. Four of these divisions cover the sector threatened by the French offensive and belong principally to XII and XXIV Army Corps. German forces have orders to avoid a major battle in the exposed frontier zone and fall back towards their prepared positions in the Westwall, leaving minefields, demolitions and small covering detachments to delay the French advance.

French forces continue their cautious advance into the Saarland. North of Bliesbrück, Renault R35 tanks of the 20e Bataillon de Chars de Combat, supporting the 4th Army, enter a German minefield, with four tanks disabled or destroyed.

German minefields and demolitions increasingly restrict the French advance, requiring engineers to clear routes before infantry and armour can move forward. German troops meanwhile continue their delaying actions in the frontier zone, while the main defensive positions remain centred on the Westwall.

The French advance remains largely uncontested and now occupy much of the Warndt Forest and a growing number of evacuated border villages, including Wadgassen, Großrosseln, Gersheim, Medelsheim and Lauterbach. The 26th Infantry Regiment (11e division d'infanterie) takes Sitterswald, dubbed "Hitlersdorf" in contemporary French press and propaganda accounts.

Later that afternoon, elements of the French 42nd Infantry Division cross the border and push into the wooded heights near Apach and Perl to secure forward positions.

Under cover of first light, local German forces, including elements of the 79th Infantry Division backed by local Grenzschutz (Border Guard) battalions, launch a counter-attack against the French 42nd Infantry Division, successfully clearing the woods occupied the previous day and driving the French back towards Apach. At approximately 16:00, following an intense artillery bombardment of the German positions, French infantry and light armour launch a successful counter-attack, retaking the lost forward positions by early evening. The day's fighting results in 20 to 40 German casualties (killed and wounded), primarily from the heavy French artillery preparation during the counter-attack, while the French suffer between 15 and 30 killed, wounded or missing, along with several light armoured vehicles damaged during the woodland fighting.

The French 9th and 11th Infantry Divisions (XX Army Corps, 4th Army), together with the 8th, 16th and 24th Infantry Divisions (XV Army Corps, 5th Army), continue their cautious advance through the Warndt Forest and the Blies Valley towards Merzig, Saarbrücken and Überherrn. By evening, leading French units reach the outer defensive belt (Vorfeld) of the German Westwall (Siegfried Line). Encountering heavy minefields, dragon’s teeth and pillbox strongpoints, French commanders halt their forward momentum, unwilling to launch a deliberate assault against the fortifications without adequate heavy-artillery support and preparation. German artillery and French batteries begin exchanging heavier fire as the French advance approaches the prepared defences of the Westwall.

The 32nd Infantry Regiment, 23rd Infantry Division, captures Brenschelbach, during which Captain Vignaud, Sergeant Kieffer and seven other French soldiers are killed. French forces now reach the high-water mark of the Saar Offensive, having occupied a belt of German territory approximately 25 kilometres long and between 5 and 8 kilometres deep.

At Abbeville in northern France, French Prime Minister Édouard Daladier and British Prime Minister Neville Chamberlain meet for the first session of the Anglo-French Supreme War Council.

General Maurice Gamelin’s Directive No. 4 is approved, ordering French forward units to cease active offensive operations, secure supply corridors through the mined border zones, dig in and consolidate their positions along the outer approaches to the Westwall. This effectively ends any plans to transform the limited Saar advance into the large-scale offensive originally planned.

The Polish government is not informed of this decision, with French communications maintaining the pretence that preparations are proceeding and that a major, full-scale offensive will commence on 17th September.

With French forces working to fortify their forward positions, artillery duels intensify across the sector. French 155 mm GPF guns and 220 mm mortars from the 109e and 155e Heavy Artillery Regiments and the 151e Positional Artillery Regiment fire counter-battery missions against German artillery positions embedded within the Westwall near Saarbrücken and Merzig.

In response, German 10.5 cm and 15 cm batteries from Artillerie-Regiment 179 and 1st Armee's heavy artillery detachments (schwere Artillerie-Abteilungen) direct harassing fire against pioneer units of the French 4th Army clearing minefields and booby-trapped obstacles in the Warndt Forest.

The head of the French Military Mission in Poland, General Louis Faury, officially notifies the Polish Chief of Staff, General Wacław Stachiewicz, that the promised major assault on the Western Front is postponed from 17th September to 20th September. In reality, the Anglo-French Supreme War Council has already suspended the offensive at its meeting the previous day.

With offensive movement completely suspended, French photo-reconnaissance aircraft from Groupe de Reconnaissance I/52, flying Potez 637s, carry out strategic mapping flights over the Saar Basin to photograph Westwall bunker layouts. Escorted by Curtiss H75 fighters from Groupe de Chasse I/5, the French aircraft are intercepted in strength over the border and engaged by Messerschmitt Bf 109Es of Jagdgeschwader 53 ("Pik As"), operating from Trier and Saarbrücken-Ensheim. In the resulting dogfights, one French Potez reconnaissance aircraft is shot down near Ensdorf, while one German Bf 109 is damaged and forced down near Saarbrücken.

Following news of the Soviet invasion of Poland earlier that morning, General Maurice Gamelin officially reaffirms the halt order issued on 12th September to the French High Command. With the final collapse of Polish resistance now imminent and a rapid German redistribution of forces westward expected, Gamelin formally places the Saar sector on a defensive footing, with French troops holding roughly 200 square kilometres of captured German border territory.

Gamelin, now anticipating that the Germans will launch counter-attacks once forces released from the campaign in Poland arrive, issues operational instructions directing French combat engineers to begin laying extensive minefields and booby-trapping road junctions, bridges and forest tracks across the Warndt Forest and along the approaches to the Maginot Line, turning the occupied German border sector into a defensive zone designed to delay any German advance.

German border units (Grenzschutz) and forward elements of the 79th Infantry Division, specifically detachments from Infanterie-Regiment 208 and Aufklärungs-Abteilung 179, conduct active combat reconnaissance patrols against French outposts near Blieskastel, confirming that French forces have transitioned to a defensive posture.

On the date previously promised to the Polish High Command for the launch of a major French offensive, the front remains quiet except for a sharp local counter-attack by units of the German 268th Infantry Division against screening forces of the French 24th Infantry Division (5th Army) near Hornbach. The attack is quickly repulsed by concentrated French artillery fire, resulting in light casualties on both sides and no change in the front line. The engagement underscores the growing aggressiveness of German forces in this sector.

With organised Polish resistance visibly collapsing, General Maurice Gamelin issues orders for French forces in the Saar sector to prepare for a general withdrawal towards their original positions behind the Maginot Line, leaving covering forces in German territory to protect the withdrawal. The decision effectively eliminates any remaining possibility of renewing the offensive and shifts French strategy on the Western Front firmly towards the defensive.

General Gamelin issues General Directive No. 5 to General Georges, Commander of the North-Eastern Front, detailing the operational plan for a phased withdrawal from German territory. The directive orders the immediate, covert removal of all non-essential heavy equipment, heavy artillery batteries (Artillerie Lourde sur Voie Ferrée and heavy tractor-drawn units) and corps-level logistical elements to positions south of the Franco-German border. As part of this process, the 4th Colonial Infantry Division and 11th Infantry Division (4th Army) begin disengaging their heavy baggage trains and divisional artillery supply units from the Warndt Forest and Saarbrücken sectors under cover of darkness.

With the German 1st Army having received six additional divisions, the 215th, 257th, 262nd, 263rd, 267th and 268th Infantry Divisions, as reinforcements since the start of the Saar Offensive, German probing actions intensify near Saarbrücken and in the Warndt Forest as intelligence confirms that the main French forces are pulling back. In the Saarbrücken sector, detachments from the German 215th Infantry Division (XXIV Army Corps) and attached Grenzschutz (Border Protection) units make contact with French rearguards from the 11th and 21st Infantry Divisions, supported by 75 mm field artillery batteries. These rearguards inflict minor casualties on the Germans, primarily through minefields and delayed artillery fire, while successfully slowing German efforts to clear obstacles along the withdrawal routes.

Elements of the German 257th Infantry Division launch a sharp reconnaissance-in-force (Gewaltsame Aufklärung) operation near Biesingen to disrupt the withdrawal of French logistical units. Screening forces from General Arlabosse’s 11th Infantry Division repulse the probing force, supported by heavy artillery batteries firing from behind the Maginot Line. The concentrated artillery fire suppresses the German units, allowing French corps-level logistical echelons to continue evacuating forward ammunition dumps and supply depots unhindered.

General Erwin von Witzleben issues preliminary planning directives to the 1st Army's corps commanders for a local counter-offensive to recover the German territory occupied during the Saar Offensive once veteran divisions redeploying from Poland arrive. Concurrently, French combat engineers begin the systematic destruction or removal of military infrastructure, telephone lines and bridges within the 8-kilometre occupied border belt to delay any future German pursuit.

The French Armée de l'Air shifts its strategic air reconnaissance, including Groupe de Reconnaissance I/33 and II/33, to focus on deep photographic reconnaissance missions over German railheads around Pirmasens, Zweibrücken and Landau, tracking the arrival of German troop transports from the east. On the ground, contact along the outpost line subsides to sporadic sniper fire as French rearguards enforce strict camouflage and radio discipline to conceal the reduced strength of their positions.

With the Surrender of Warsaw, French military intelligence (2e Bureau) warns General Headquarters (GQG) that German divisions in Poland are now embarking on rail transports bound for the Western Front. In response, General Gamelin approves final operational timelines (Order No. 3433/3) for the withdrawal of the remaining French infantry from occupied Saar territory, directing covering troops to hold their screening positions along the frontier until early October before withdrawing to the main Maginot Line defences.

As the French continue their phased withdrawal, units of the German 18th Infantry Regiment (6th Infantry Division) launch a localised counter-attack against covering detachments of the French XX Army Corps (4th Army), primarily from the 11th and 21st Infantry Divisions in the sector between Bischmisheim and Ommersheim, southeast of Saarbrücken. The probe is quickly broken up with the support of pre-registered 75 mm artillery fire, with only light casualties on both sides.

Phase 1 of General Directive No. 5 is completed with all non-essential heavy equipment, heavy artillery batteries and corps-level logistical elements having withdrawn to prepared positions behind the Maginot Line. At the same time, French combat engineers complete the priming and booby-trapping of main road corridors, railway lines and forest tracks across the Warndt, leaving only narrow, concealed corridors open for the screening rearguards of the 3rd and 4th Armies to withdraw through. These measures create a "dead zone" intended to delay any German pursuit.

General von Witzleben issues Army Order No. 4 to the German 1st Army, detailing the operational plan for Unternehmen Herbstwind (Operation Autumn Wind), a multi-pronged counter-offensive by XII Army Corps from the Pirmasens-Zweibrücken sector and XXIV Army Corps from the Warndt-Saarbrücken sector, aimed at reclaiming the occupied areas of the Saar border region. The offensive is scheduled for 16th October and is to be conducted by recently mobilised divisions, including the 215th, 257th and 268th Infantry Divisions, supported by heavy corps artillery groups. Veteran divisions returning from Poland are to remain in reserve behind the Westwall.

French infantry divisions along the front complete the transfer of local screening responsibilities to more specialised light covering detachments. These units are to maintain dummy fires and sporadic mortar fire to simulate full unit strength, allowing the main infantry formations to begin road marches back towards the French frontier under cover of darkness.

Under cover of bad weather and strict night discipline, the French 3rd Army (General Condé) and 4th Army (General Réquin) begin executing Phase 2 of General Directive No. 5, disengaging their main combat divisions from the forward sectors and moving them back in staged road marches towards the Maginot Line fortifications. Screening responsibilities are left entirely to light covering detachments.

Combat patrols from the German 215th and 257th Infantry Divisions detect a significant drop in French artillery activity and identify a number of abandoned forward positions south of Saarbrücken. General von Witzleben orders XXIV Army Corps to cautiously probe forward into the Warndt Forest to test French strength. The advancing German units encounter minimal resistance from French covering detachments but find extensive minefields, booby traps and demolished road junctions. With engineers required to clear routes through these obstacles, German forward movement remains slow.

The remaining French rearguard detachments trigger pre-mined bridge demolitions across the Saar and Blies Rivers, notably destroying key spans at Grosbliederstroff, Habkirchen and Reinheim along the border corridors. By the early hours of the 15th, all French forces have withdrawn across the pre-war frontier, thereby fulfilling Phase 2 of General Directive No. 5 and completing the withdrawal from German territory into the fortified positions of the Maginot Line.

The German 1st Army completes its final preparations for Unternehmen Herbstwind (Autumn Wind), having assembled nine assault divisions supported by approximately 532 divisional and corps-level guns and mortars, together with nearly 200 fighter, reconnaissance and bomber aircraft from Luftflotte 3 (Fliegerkorps I).

In the western sector (Warndt–Saarbrücken), XXIV Army Corps concentrates the 215th, 257th, 267th and 268th Infantry Divisions, while XII Army Corps, comprising the 52nd, 75th, 258th, 262nd and 263rd Infantry Divisions, prepares to advance in the eastern sector (Pirmasens–Zweibrücken). In reserve behind the Westwall are the 6th, 9th, 15th and 36th Infantry Divisions. With artillery batteries across both corps having completed registration fire against French forward border positions and air reconnaissance confirming that the main French forces are now fully withdrawn behind the frontier and into the Maginot Line defences, von Witzleben issues his final authorisation for the assault divisions to move into their jump-off positions.

At 06:00, General Erwin von Witzleben's 1st Army launches Unternehmen Herbstwind. Supported by heavy artillery bombardments and Luftwaffe air support, the nine divisions of XXIV and XII Army Corps begin their advance into the Saarland border belt along two primary axes. Finding the area evacuated, German assault columns push through the booby-trapped "dead zone". In the western sector, lead reconnaissance elements of the 257th and 268th Infantry Divisions (XXIV Corps) move south through the Warndt Forest and the area south of Saarbrücken, making initial contact with French screening detachments near Forbach and Grosbliederstroff between 15:30 and 16:30.

In the eastern sector, the 52nd and 258th Infantry Divisions (XII Corps) move southwest across the Blies River and through the Hornbach corridor, reaching the French security perimeter screening the Bitche, Rohrbach and Sarreguemines sectors between 17:00 and 18:00. By dusk (around 18:45), the German advance halts along the line of destroyed river crossings and heavily mined obstacles directly facing the principal French outpost line, approximately 3 to 5 kilometres in front of the Maginot Line's main defensive positions.

With its immediate objectives accomplished, German offensive operations come to an end, though sporadic patrol firefights and heavy artillery exchanges continue into the night. Over the course of Operation Saar and Unternehmen Herbstwind, despite significant structural damage to the border region, total casualties remain relatively light, with French forces suffering approximately 2,000 killed, wounded or missing, while total German losses stand at 666 killed, wounded or missing.