Fortified Sector of the Sarre

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.

Compared with much of the French border with Germany and Luxembourg, the valley of the Sarre was not heavily fortified. As long as the Saarland was demilitarized, the sector did not face a significant military threat. With the union of the Saarland with Germany in 1935, the area posed a greater threat. The shallow water tables in the area prevented deeply buried fortifications of the Maginot type in most of the sector, but presented opportunities for the defensive use of inundations. A system of reservoirs feeding diked impoundments gave France the ability to rapidly flood the valleys of the Nied and Moderbach rivers. The necessary dams, weirs and dikes were defended by blockhouses, and were themselves strongly built. Work had already taken place to inundate the Sarre, Albe and Modebach. Work on inundations of the Nied started in 1934. Construction of casemates to cover the flooded areas started in 1935. Three ouvrages armed with 75mm gun turrets were proposed: Remmerberg, Vahl-Ebersing and Valette, but funding difficulties prevented their construction. Only the petit ouvrage Haut-Poirier was built. The western part of the sector did not use inundations, relying on blockhouses along the Nied.

The weakness of the western portion of the sector was cause for concern during the Phoney War of 1939-40, resulting in the construction of the CEZF Line (Commission d'Étude des Zones Fortifiées), or Second Position, to the rear of the four western sub-sectors. A number of blockhouses were built under the auspices of the Service Technique du Génie (STG), but the line was incomplete in 1940, with long gaps between blockhouses.

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