Fortified Sector of Haguenau The Fortified Sector of Haguenau ( " Secteur Fortifiée de Haguenau " ) was the French military organization that in 1940 controlled the most easterly section of the Maginot Line , to the north of Strasbourg . The left ( western ) wing of the Haguenau sector adjoined the Fortified Sector of the Vosges , includes two of the largest Maginot fortifications , Ouvrage Hochwald and Ouvrage Schoenenbourg . The right wing , started after 1931 , was progressively scaled back in order to save money during the Great Depression , abandoning plans for four " petit ouvrages " and substituting casemate s . The sector ' s northern and eastern sides bordered on Germany . To the south the sector borders the Fortified Sector of the Lower Rhine , from which it received several casemates in a boundary shift in 1940 . The SF Haguenau was attacked in 1940 by German forces in the Battle of France . The sector successfully fended off German assaults before the Second Armistice at Compiègne . The positions and their garrisons finally surrendered on 1 July 1940 . The sector saw action again in 1944 and 1945 as American forces advanced into Alsace . The sector ' s easternmost sections saw heavy fighting in January 1945 during the German Operation Nordwind offensive . Following the war some positions were reactivated for use during the Cold War , with continued use of Ouvrage Hochwald as an air defense command center to the present day . Ouvrage Schoenenbourg has been preserved as a museum and is open to the public , as well as the Casemate d ' Esch . Concept and organization . The Haguenau sector was part of the larger Fortified Region of the Lauter , a strongly defended area between the Sarre to the west and the Rhine valley to the east . The Lauter region was more important during the planning and construction phase of the Maginot Line than it was in the operational phase of the Line , when the sectors assumed prominence . The Fortified Region of the Lauter was dissolved as a military organization on 5 March 1940 , becoming the 43rd Fortress Army Corps . The Haguenau sector uniquely combined two aspects of the Maginot fortifications : two " gros ouvrages " of the largest kind in the west , and lighter casemate lines farther east , with multi - layered lines of casemates along the Rhine . The sector thus forms a transition from the heavily fortified section of the central Line to the lighter positions along the Rhine sectors . In preliminary planning in1925 the " Commission de Défense des Frontiers " regarded the Rhine and its branches as a significant obstacle , backed by the heights of the Vosges . The Hochwald and Schoenenbourg positions were planned to anchor the right flank of the Maginot defenses on the easternmost heights of the Vosges . To the south , Strasbourg was to be considered an open city , as it could otherwise be easily destroyed by German artillery on the other side of the Rhine . The Herrlisheim sub - sector of the neighboring Fortified Sector of the Lower Rhine was transferred to the SF Haguenau on 5 March 1940 when the SF Lower Rhine was reorganized as the 103rd Fortress Infantry Division . The riverbank fortifications were of a basic nature , with protection only up to 155mm caliber , machine gun armament and no electrical system . The second and third lines were more robust in construction and equipment , with electric generators and anti - tank weapons . Command . The Haguenau sector was under the overall command of the French 5th Army , headquartered at Wangenbourg , under the command of General Bourret , which was in turn part of Army Group 2 under General André - Gaston Prételat . The SF Haguenau was commanded by Commandant Laherre , then Lieutenant Colonel Schwartz . The command post was located at Reimerswiller , although Schwartz ' s command post was at Hochwald . The interval troops , the army formations that were to provide the mobile defense for the sector , to support and be supported by the fixed defenses , were under the command of the 12th Corps ( " 12e Corps d ' Armee " ) , General Dentz , commander . The 6th Corps was in turn made up of the 16th and 70th Infantry Divisions . Artillery support for the sector was provided by the 156th Position Artillery Regiment ( " Régiment d ' Artillerie de Position ( RAP ) " ) , which controlled both fixed and mobile artillery , commanded by Lieutenant Colonel Duval . The 16th ID was a Class A reserve formation , while the 70th ID was a Class B reserve division , unsuitable for heavy or sustained combat . At the midpoint of the Battle of France on 1 June 1940 , the fortress troops of the SF Haguenau amounted to five fortress infantry regiments in 12 battalions , comprising 670 officers and 22 , 000 men . Description . The sector includes , in order from west to east , the following major fortified positions , together with the most significant casemates and infantry shelters in each sub - sector : Sub - sector of Péchelbronn . 22nd Fortress Infantry Regiment ( " 164e Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Lt . Colonel Lemai , followed by Chef de Bataillon Fabre in May 1940 , command post in the Bois de Kirschpiel . Peacetime barracks and support : Sub - sector of Hoffen . 79th Fortress Infantry Regiment ( " 79e Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Lt . Colonel Rethoré , command post at position 1416 , then the Abri du Bucholzberg from 17 June 1940 . Peacetime barracks and support : Sub - sector of Soufflenheim . 23rd Fortress Infantry Regiment ( " 23e Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Lt . Colonel Lefèvre , command post at Soufflenheim . Peacetime barracks and support : Sub - sector of Sessenheim . 68th Fortress Infantry Regiment ( " 68e Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Lt . Colonel Blanloeil . Peacetime barracks and support : Sub - sector of Herrlisheim . 70th Fortress Infantry Regiment ( " 70e Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Lt . Colonel Schwartz , then Raynaud from April 1940 . Transferred from the SF Lower Rhine 5 March 1940 . 9th CEC . CEC = " Compangnie d ' Équipage de Casemates " ) , or " casemate company " 10th CEC . Peacetime barracks and support : History . Battle of France . Hochwald was the first " ouvrage " to fire on the Germans on 8 – 9 September 1939 during the Phoney War , supporting French forces involved in the Saar Offensive . A number of problems with ammunition and weaponry were revealed by this action , and compatibility problems with guns and ordnance persisted into 1940 in other locations . Hochwald and Schoenenbourg fired their 75mm guns again on 16 October Hochwald fired again in November on Germans laying a minefield . At Schoenenbourg a 120mm gun exploded during target practice in March 1940 . The full German offensive opened on 10 May 1940 . German attention was concentrated on Belgium and the Ardennes region , breaching a weak point in French frontier defenses at Sedan . The main Maginot Line was not directly attacked . However , as disaster overtook the French field armies , the interval troops were pulled out of the Line on 15 June in the central Line , but remained in the SF Haguenau . Having broken through at the Sarre , German troops moved behind the Line , heading east . Hochwald and Schoenenbourg came under aerial and artillery attack on 19 June , continuing the next day . Hochwald supported Lembach with its 75mm guns when the latter came under infantry attack , but the German 215th ID broke through a weakly fortified section of the Line west of Lembach in the SF Vosges . On 21 June a German 420mm mortar and a 355mm weapon began shelling Schoenenbourg , causing some damage but not breaching the position . Schoenenbourg received the heaviest bombardment of any Maginot fortification , comprising 160 aerial bombs , 50 42 cm shells , 33 28 cm shells , and approximately 3000 smaller projectiles , In early June in the face of the German assault , all fortress units attached to the Fifth Army were ordered to prepare for withdrawal to the south and west . While fortress units under the 2nd , 3rd and 8th Armies received categorical instructions to prepare to sabotage their positions and conduct an orderly retreat from 14 to 17 June , Fifth Army commander General Bourret ' s instructions to the SFs Rohrbach , Vosges , Haguenau and Lower Rhine were not as definitive . The personnel of the SF Haguenau were to be consolidated into a " Division de Marche " entitled the DM " Regard " , consisting of the I / 22 , II / 23 , XXI / 23 , I / 68 , II / 68 , II / 70 , II / 79 and III / 79e RIFs , along with the 69e RAMF and the 156e RAP . A partial withdrawal of fortress troops took place in the SF Haguenau , with some battalions of each fortress infantryregiment remaining in their positions until the armistice to cover the withdrawal of the interval troops and the fortress infantry assigned to the " divisions de marche " . None of the major positions in the SF Haguenau were captured by German forces prior to the 25 June armistice . However , by 20 June the town of Haguenau to the rear of the Line had been captured by the German 215th Infantry Division , part of a German strategy to secure the Pechelbronn oilfield . To support the 215th ID , the German 246th Infantry Division was ordered to directly attack the SF Haguenau from the north . On the 20th the 246th attacked several casemates centering on Oberroeden Nord and Aschbach - Ouest and Est . Aerial bombing hit Oberroeden Nord and the Abri de Hoffen , disrupting communications but not seriously harming French defenses . German artillery hit an embrasure at Oberroeden Sud , killing one French soldier . Despite the intensity of the attack , the casemate line , aided by Hochwald and Schoenenbourg , held . The 246th withdrew with sixty - two killed , ten missing and about three hundred wounded . The Second Compiègne armistice took effect on 25 June , stopping the fighting . The final surrender of Hochwald , Schoenenbourg and their lesser positions was effected on 1 July 1940 , in accordance with the terms of the armistice . Hochwald had fired 19 , 550 of the 75mm , 135mm or 81mm rounds of the 90 , 315 on hand ; Schoenenbourg 16 , 474 of 34 , 260 . Under German occupation in 1940 , Schoenenbourg was subjected to a new bombardment , filmed for propaganda purposes . In 1944 Hochwald ( " Werk Hochwald " ) was used as an underground factory . Units . The 22nd RIF was deployed in the Pechelbronn area . The unit ' s first battalion was ordered to withdraw from the fortified line on 14 June as part of the DI " Regard " , falling back to Lure , then Héricourt to control the Besançon - Belfort road . The battalion was captured at Héricourt on 19 June . The other units of the 22nd RIF remained in their fortifications and surrendered on 1 July . The 23rd RIF was stationed in the Soufflenheim sub - sector . The sub - sector experienced bombardments beginning 14 May , with direct assault finally beginning 13 June , at the same time as orders arrived to detach the second and 21st battalions to the DF " Regarde " . The second battalion was sent to Vesoul , then to Lure , while the 21st was ordered to Sainte - Croix - aux - Mines and the Col de Sainte - Marie . The battalions saw action at several locations in the Haute - Saône before finally being captured on the 25th in the Vosges . The first battalion and CEC ( " compagnie d ' équipage de casemates " ) 5 and 6 remained in their fortifications to surrender on 2 July . The 68th RIF occupied the sub - sector of Sessenheim . From 14 June the first and second companies were attached to the DF " Regard " and were assigned to guard the rail line between Épinal and Vaivre , the first company assigned to an area near Vesoul , and the second at Sainte - Marie - aux - Mines . Both were captured between 19 and 22 June . The third battalion , left behind in the casemates , repelled attacks on 16 and 17 June and surrendering on 30 June . The 70th RIF . manned the Herrlisheim sub - sector . Transferred from the Lower Rhine to the Haguenau sector on 5 March 1940 , the regiment lost its first and second nb \ battalions to the 70 / 79 " régiment de marche " on 13 June . The formation was integrated into the 103rd DIF ( the former SF Lower Rhine ) and moved to Plaine and Diesbach . After the armistice the units moved to Salm and were captured on 25 June . The casemate garrisons became part of the so - called " groupement Schwartz " after the sector ' s commander , and were repositioned to face to the south in the direction of the German 215th ID ' s threat . They surrendered on 2 July . Operation Nordwind . While the Haguenau positions played little role in Allied advances in 1944 , the retreating Germans caused significant damage to Hochwald , blowing up turrets , entrance blocks and several combat blocks before abandoning the position . Somewhat later , in 1945 , Schoenenbourg and nearby casemates Schmeltzbach Ouest , Drachenbronn Nordand Sud and Bremmelbach received the same treatment from the German 245th ID before the American 36th Infantry Division took possession . In the Alsace Plain Ingolsheim Nord and Ouest , Hunspach Village , Seltz and others were blown up . The eastern portion of the sector was the scene of heavy fighting in January 1945 as a result of the German Operation Nordwind offensive aimed at the recapture of Strasbourg . German forces of Army Group G attacked the U . S . 7th Army and French First Army . American units retreated south to the casemate line and dug in , holding on from 8 January to 21 January , before falling back to Haguenau . " Môle de Haguenau " . Following World War II , the French military reclaimed the Maginot Line with the aim of renovating and improving it against a possible attack by Warsaw Pact forces . The strongest positions , Hochwald and Schoenenbourg were grouped with Four - à - Chaux and Lembach from the SF Vosges . They were designated the " môle de Haguenau " ( " breakwater " ) in 1951 and were placed back into service after a period of rehabilitation . After the establishment of the French nuclear strike force , the importance of the Line declined , and maintenance ceased in the 1970s , with most of the casemates sold . in 1956 , Hochwald was transferred to the French Air Force for use as an air defense command center . New underground galleries were built in the rear ( i . e . , near the entrance blocks ) . The nearby Caserne de Drachenbronn became the above - ground support and operations facility . The complex was briefly known as " Ouvrage H " before its designation as " Base Aérienne 901 Drachenbronn " . Present status . On 4 September 2001 , Schoenenbourg was the first " gros ouvrage " to be sold by the Ministry of Defense to a local community . Schoenenbourg is maintained as a museum and may be visited . The Casemate d ' Esch is maintained as a museum by the same organization . The site is notable for the American M4 Sherman tank perched on top of the casemate . Hochwald remains in French military hands , housing the hardened command center for French Air Force activities at Drachenbronn Air Base / BA 901 . Its former caserne provides support and above - ground operational functions . The Bockange caserne is a paintball range . The Casemate d ' Oberroedern Sud is maintained as " Casemate Rieiffel " by the " Association des Amis de la Ligne Maginot d ' Oberroeden " , which has restored the casemate since 2001 . The organization is also working on the casemates at Aschbach Est , Aschbach Ouest and Bois d ' Hoffen , however these are not presently open to the public . The Abri du Heidenbuckel has been preserved by the " Association des Amis du Heidenbuckel " , and is open at times during the summer . The Casemate de Kilstett is under restoration