Question: Who was the French military organization that in 1940 controlled the section of the Maginot Line between the French border with Belgium and Maubeuge in the battle know as The Fall of France?
Context: The Battle of France, also known as the Fall of France, was the German invasion of France and the Low Countries during the Second World War.  In six weeks from 10 May 1940, German forces defeated Allied forces by mobile operations and conquered France, Belgium, Luxembourg and the Netherlands, bringing land operations on the Western Front to an end until 6 June 1944.  Italy entered the war on 10 June 1940 and attempted an invasion of France. The Fortified Sector of Lille ("Secteur Fortifié de Lille") was the French military organization that in 1940 controlled the section of the French border with Belgium opposite Lille.  The sector was part of a system of fortifications that included the Maginot Line in other sectors.  In the case of the Lille sector, no large fortifications of the kind typified by the Maginot Line were built in the area.  Fortifications were confined to a total of 65 blockhouses and 23 infantry shelters within a few kilometers of the border, mainly between Roubaix and Tourcoing and the border.  The Fortified Sector of Lille was bordered on the east by the Fortified Sector of the Escaut and on the west by the Fortified Sector of Flanders.  The sector figured in the Pillbox affair of 1939-40.  It was quickly overrun by German forces during the Battle of France. The Fortified Sector of Montmédy ("Secteur Fortifié de Montmédy") was the French military organization that in 1940 controlled the section of the Maginot Line between Sedan and Longuyon, a distance of about 60 km .  The sector was not as strongly defended as other sections of the Maginot Line, facing the southern Ardennes region of Belgium.  Large portions of the Montmédy sector were defended by fortified houses, blockhouses, or casemates.  The sector includes only four "ouvrages" of the type found in stronger sections of the Line.  The weakly defended area in front of Sedan was the scene of a major breakthrough by German forces in the opening of the Battle of France.  This was followed by a German assault on the Maginot Ouvrage La Ferté, which killed the entire garrison, the only such event on the Maginot Line. The Fortified Sector of Maubeuge ("Secteur Fortifié de Maubeuge") was the French military organization that in 1940 controlled the section of the Maginot Line between the French border with Belgium and Maubeuge, a distance of about 70 km .  The sector was not as strongly defended as other sections of the Maginot Line Large portions of the Maubeuge sector were defended by blockhouses or casemates.  The sector includes only four "ouvrages" of the type found in stronger sections of the Line, arranged in an arc to the north and east of the fortified city of Maubeuge, incorporating defenses from the First World War.  The Maubeuge sector and the Fortified Sector of the Escaut were the final sections of the Maginot line to be authorized, and were termed the "New Fronts."  In the Battle of France the large fortifications of Maubeuge successfully resisted determined German bombardments and infantry attacks, despite their failure to protect Maubeuge against the Germans, who had outflanked the defensive line and who assaulted the fortification lines from the rear.  Surrender or evacuation came only after the positions were surrounded and cut off from any hope of reinforcement.  One "ouvrage" and one pre-Maginot fortification have been preserved. The Fortified Sector of Thionville ("Secteur fortifié de Thionville") was the French military organization that in 1940 controlled the section of the Maginot Line immediately to the north of Thionville.  The sector describes an arc of about 25 km , about halfway between the French border with Luxembourg and Thionville.  The Thionville sector was the strongest of the Maginot Line sectors.  It was surrounded but not seriously attacked in 1940 by German forces in the Battle of France, whose main objective was the city of Metz.  Despite the withdrawal of the mobile forces that supported the fixed fortifications, the sector successfully fended off German assaults before the Second Armistice at Compiègne.  The majority of the positions and their garrisons finally surrendered on 27 June 1940, the remainder on 2 July.  Following the war many positions were reactivated for use during the Cold War.  Four locations are now preserved and open to the public. The Fortified Sector of the Escaut ("Secteur Fortifié de l'Escaut"), also known as the Fortified Sector of the Schelde, was the French military organization that in 1940 controlled the section of the Maginot Line between the French border with Belgium and Valenciennes, a distance of about 30 km .  Named for the Escaut River (more commonly known as the Schelde), the Maginot line in the Escaut sector consists of a single position, the "petit ouvrage" Eth, together with its supporting casemate Jeanlain, as well as an upgraded fort of the Séré de Rivières system, the Fort de Maulde.  The remainder of the sector's fortifications consist of blockhouses and casemates arranged along a line of principal resistance about 2 km behind the frontier, with a second line on the edge of the Raismes Forest.  The Escaut sector and the Fortified Sector of Maubeuge were the final sections of the Maginot line to be authorized, and were termed the "New Fronts."  The Escaut sector was attacked during the Battle of France in late May 1940, resisting for a few days. The Fortified Sector of Flanders ("Secteur Fortifié des Flandres") was the French military organization that in 1940 controlled the section of the French border with Belgium between Lille and the North Sea.  The sector was part of a system of fortifications that, in other sectors, included the Maginot Line.  In the case of the Flanders sector, no large fortifications of the kind typified by the Maginot Line were built in the area.  Fortifications were confined to almost two hundred blockhouses built during the 1930s, and some defensive inundations in the vicinity of Dunkirk.  The Fortified Sector of Flanders was bordered on the east by the Fortified Sector of Lille It was quickly overrun by German forces during the Battle of France. The Fortified Sector of the Crusnes ("Secteur Fortifiée de la Crusnes") was the French military organization that in 1940 controlled the section of the Maginot Line extending eastwards approximately 28 km from Longuyon.  The sector roughly follows the valley of the Crusnes river.  Crucially, the trace of the Maginot Line in the Crusnes sector is about 7 km "behind" the industrial city of Longwy which sits directly against the French borders with Belgium and Luxembourg.  The Crusnes sector was one of the strongest Maginot Line sectors.  It was attacked in 1940 by German forces in the Battle of France.  Despite the withdrawal of the mobile forces that supported the fixed fortifications, the sector successfully fended off German assaults before the Second Armistice at Compiègne.  The positions and their garrisons finally surrendered on 27 June 1940.  Following the war many positions were reactivated for use during the Cold War.  Three locations are now preserved and open to the public, with a fourth position under restoration. The Fortified Sector of Rohrbach ("Secteur Fortifié de Rohrbach") was the French military organization that in 1940 controlled the section of the Maginot Line in the vicinity of Bitche.  The sector was bordered to the west by the Fortified Sector of the Sarre and to the east by the Fortified Sector of the Vosges.  With lower priority than other sectors, the SF Rohrbach was built somewhat later than its neighbors to the east and west, and in company with positions on the extreme western end of the Maginot Line, became one of the "New Fronts."  The sector contains several major "ouvrages" and was the scene of fighting in both 1940 and 1944.  It was attacked in 1940 by German forces in the Battle of France.  The sector was heavily engaged by German forces in mid-June 1940, with several casemates and the "petit ouvrage" Welschhof surrendering before the Second Armistice at Compiègne.  The remaining positions and their garrisons finally surrendered on 27 June 1940.  In 1944 German forces occupied several positions in the SF Rohrbach, forcing advancing American forces to attack them individually or to bypass them.  The German Operation Nordwind offensive of early 1945 caused American forces to fall back, returning to complete the capture of the Rohrbach sector in March 1945.  Following the war many positions were reactivated for use during the Cold War.  Two locations are now preserved and open to the public. The Fortified Sector of the Sarre ("Secteur Fortifié de la Sarre") was the French military organization that in 1940 controlled the section of the Maginot Line on either side of the Sarre river.  The sector's defenses relied primarily on a system of inundations that could be created by fortified dikes and regulating weirs, backed by blockhouses.  Weakly defended compared with other sections of the Maginot Line, the sector received a measure of attention and funding from the mid-1930s when the formerly demilitarized Saarland was reintegrated into Germany.  However, with a single "petit ouvrage" it remained a weak point in the Line.  In 1940 the Sarre sector was attacked by German forces in the Battle of France.  The inundations were only partly successful, and German forces were able to pierce the Maginot Line at the Sarre, allowing German divisions to move behind the main French line.
Answer: Fortified Sector of Maubeuge