Fortified Region of Metz

The region was established in 1926 as a military organization for the French fortifications along the frontier with Luxembourg and Germany to the east of Longuyon in northeastern France, forming a shield to the north of the industrialized areas of Metz and Thionville.

With the recovery of these territories following World War I, most of the Séré de Rivières forts were deep in the interior of northeastern France and not useful.

[2] The Conseil Supérieure de la Guerre ('Supreme War Council') created a committee in March 1920 to study France's newly adjusted frontiers, with Marshal Joseph Joffre as chairman.

[3] The RF Metz was again proposed in 1922 by the Territorial Defense Commission (commission de défense du territoire), which identified potential invasion routes from Germany into France at three locations: the Belfort Gap, between the Vosges Mountains and the Rhine, and across the Lorraine plateau, the last two directly affecting the Metz industrial basin, home of much of France's coal and steel industry.

The report formalized the concept of the fortified region, to be about 60 kilometres (37 mi) in depth, a distance dictated by the range of heavy artillery.

This allowed optimal siting of fortifications on the heights behind Longwy, rather than contending with the town's basin and its close proximity to the border.

[7] The Commission d'Organisation des Régions Fortifiés, or CORF, was established on 30 September 1927 to oversee the design, financing and construction of the Maginot Line.

[14] However, budget cuts were felt in the eastern wing, where the expansion of several petit ouvrages was deferred to 1940, never started after war threatened.

[1] The Fortified Region of Metz was disestablished on 18 March 1940, two months before the Battle of France, with Army command exercising a more direct control over the four sectors.