The ', renamed fort Decaen by the French in 1919, is a military installation near Metz. It is part of the first fortified belt of forts of Metz and had its baptism of fire in late 1944, when Battle of Metz occurred. == Historical context == The first fortified fort belt of Metz consists of forts de Saint-Privat (1870), of Queuleu (1867), des Bordes (1870), Saint-Julien (1867), Gambetta, Déroulède, Decaen, Plappeville (1867) and St. Quentin (1867), most of them unfinished in 1870, when the Franco-Prussian War burst out. During the Annexation, the German garrison at Metz will oscillate 15,000 and 20,000 men at the beginning of the period〔.〕 and will exceed 25,000 men just before the First World War,〔.〕 gradually becoming the first stronghold of German Reich.〔François Roth, « Metz annexée à l’Empire allemand », dans François-Yves Le Moigne, Histoire de Metz, Toulouse, Privat, , p. 350.〕