Fortified Sector of the Vosges The Fortified Sector of the Vosges ( " Secteur Fortifiée des Vosges " ) was the French military organization that in 1940 controlled the section of the Maginot Line at the northern end of the Vosges Mountains in northeastern France . The sector was bordered to the west by the Fortified Sector of Rohrbach and to the east by the Fortified Sector of Haguenau . The sector featured two " gros ouvrages " mounting heavy artillery at either end of the sector and one " petit ouvrage " mounting infantry weapons , linked by a line of casemate s . The sector was attacked in 1940 by German forces in the Battle of France . German forces penetrated the casemate line and moved behind French lines . Despite the withdrawal of the mobile forces that supported the fixed fortifications , the three " ouvrages " successfully fended off German assaults before the Second Armistice at Compiègne , but were unable to hinder German activities to their south . The positions and their garrisons finally surrendered on 1 July 1940 . Following the war several positions were reactivated for use during the Cold War . One position , Ouvrage Four - à - Chaux , is open to the public and may be visited . Concept and organization . The Vosges 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 sector was anchored at either end by Grand - Hohékirkel on the west and Lembach - Four - à - Chaux on the east . In between the Line was filled in with casemates and blockhouses , with the stretch from Glasbronn to Windstein located behind the Swachwartzbach stream . This central portion of the depended on topography for much of its defense . The central casemate line was supported by the guns of the " ouvrages " and by the late addition of the casemates of Biesenberg and Windstein , which provided lateral covering fire with 75mm guns . Three proposed " petit ouvrages " were never constructed . Command . The Vosges 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 Vosges was commanded by General Viellard , then Colonel André . The command post was at Baerenthal , then Ingwiller . 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 from the 30th Alpine Infantry Division . Artillery support for the sector was provided by the 168th Position Artillery Regiment ( " Régiment d ' Artillerie de Position ( RAP ) " ) , which controlled both fixed and mobile artillery , commanded by Lieutenant Colonel Robo . The 30th DIA was a Class A reserve formation . On 5 March 1940 the SF Vosges was reorganized and designated the 43rd Army Fortress Corps ( " 43e Corps d ' Armée de Forteresse " ) , inheriting some elements from the RF Lauter and giving up the 37th RIF to SF Rohrbach . At the midpoint of the Battle of France on 1 June 1940 , the fortress troops of the 43rd CAF amounted to two fortress infantry regiments in six battalions , comprising 525 officers and 15 , 250 men . By 13 June the 43rd CAF included the hastily assembled " divisions de marche " Senselme and Chestenet , previously the fortress units of the SF Vosges and SF Rohrbach , as well as the 30th DIA . 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 Philippsbourg . 154th Fortress Infantry Regiment ( " 154 Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Lt . Colonel Lambert 2e UEC . UEC = " Unité d ' Équipage de Casemates " ) , or " casemate unit " Sub - sector of Langensoultzbach . 165th Fortress Infantry Regiment ( " 165 Régiment d ' Infanterie de Forteresse ( RIF ) " ) , Commandant Renard , command post at Hill 1360 . 5e CEC . CEC = " Compangnie d ' Équipage de Casemates " ) , or " casemate company " 6e CEC . Peacetime barracks and support : History . Battle of France . 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 43rd CAF ( formerly SF Vosges ) were to be consolidated into a " Division de Marche " entitled the DM " Senselme " , consisting of the 154e and 165e RIFs , along with the 143 CIF ( company ) , the V / 400e RP ( " régiment de position " ) and the 59e RARF ( " régiment d ' artillerie le la région fortifié " ) . A partial withdrawal of fortress troops took place in the SF Vosges , with some battalions of each fortress infantry regiment 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 " . On 19 June 1940 , the German 215th Infantry Division attacked in the area immediately to the west of Lembach , between the river Schwartzbach and Lembach . The German objective was to break the blockhouse line between Lembach and Grand - Hohékirkel . An infantry assault on the line captured several positions . Fire support from the " ouvrages " was hampered by a lack of observing positions and bombing attacks . Lembach and Four - à - Chaux were bombed by " Stuka s " with no significant effect on their defenses . Four - à - Chaux ' s 135mm and 75mm gun turrets fired on the Germans throughout the day . However , by the end of the day the Germans had captured twenty - two casemates and blockhouses , granting the 215th ID freedom to move behind the Maginot Line and to bypass the heavier fortifications . It moved on to the vicinity of Haguenau and secured the Pechelbronn oilfield . The next day an attack on the " ouvrages " was repelled with artillery support from Hochwald . The German advance continued into the Vosges and Alsace , but did not directly attack the " ouvrages " . Lembach , Four - à - Chaux and Hochwald formally surrendered on 1 July 1940 . Units . The 154th RIF was stationed in the Philippsbourg sub - sector . The regiment absorbed the 21st battalion of the 37th RIF on 16 March 1940 . From 7 May , the 154th RIF took fire from German positions . On 12 June , the advanced posts near the border were abandoned . Some elements of the 154th RIF withdrew to Biberkirch and La Valette . The units were finally captured near the Col du Donon on 23 and 24 June , while the units that remained in their casemates surrendered on 30 June . The 165th RIF was deployed in the sub - sector of Langensoultzbach . On 14 June the regiment dteached machine gun battalions to the DM " Senselme " to defend the Marne – Rhine Canal in the area of Arzviller , but fell back to Dabo and were finally captured near Mont Donon on 25 June . The fortress troops who remained in their positions surrendered on 1 July . 1944 and 1945 . At the end of November 1944 the U . S . Seventh Army under General Alexander Patch had reached the Vosges region . Grand - Hohékirkel was occupied by elements of the German 25th Panzer Grenadier Division . Otterbiel and Grand - Hohékirkel were to be the next positions to be attacked by the U . S . 100th Infantry Division , but the planned operation was disrupted by the Battle of the Bulge . The Seventh Army withdrew to cover areas vacated by the U . S . Third Army , which moved to confront the German offensive . The 100th returned in March 1945 attacked the area on a broad front . Grand - Hohékirkel was lightly defended , and the Americans , backed up by heavy artillery , were able to capture Grand - Hohékirkel and the " Ensemble de Bitche " with few casualties . Four - à - Chaux saw little action during the Lorraine Campaign , where most action took place around Hochwald and Schoenenbourg . Block 1 was destroyed using explosives by the Germans before the surrender in 1945 . " Môle de Bitche " . 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 . Four - à - Chaux and Lembach were grouped with Hochwald and Schoenenbourg from the SF Haguenau . They were designated the " môle de Bitche " ( " breakwater " ) in 1951 and were placed back into service after a period of rehabilitation . Schiesseck , Otterbiel ( in the SF Rohrbach ) and Grand - Hohékirkel , located at the Camp de Bitche army training center , were used for training in fortress systems and weapons . During Exercise " Turenne " at Grand - Hohékirkel in 1953 , firing exercises cast doubt on the combat viability of the exposed cloches , which had proved vulnerable to German fire in the war . A follow - up exercise ( " Hoche " ) did , however , confirm that casemate positions remained secure against 90mm - equivalent gunfire , using AMX - 13 and M47 Patton tanks to fire on embrasures . 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 . Present status . Four - à - Chaux is open to the public under the guidance of the SILE " ( Syndicat d ' Initiative de Lembach et Environs ) " association . Lembach is privately owned and reported to be in poor condition . Grand - Hohékirkel is on military land and is not accessible to the public . The casemates of Dambach Nord and Dambach Sud are open for visitation , along with a trail system through the Schwartzbach valley .