Fort Issy

Fort d'Issy
Part of Fortifications of Paris
Issy-les-Moulineaux in France
Entrance to Fort d'Issy
Plan of Fort Issy around 1870
Fort d'Issy Location to the south of Paris
Coordinates	48°49′02″N 2°16′06″E / 48.817176°N 2.268391°E / 48.817176; 2.268391Coordinates: 48°49′02″N 2°16′06″E / 48.817176°N 2.268391°E / 48.817176; 2.268391
Type	Fort
Site information
Open to the public	yes
Site history
Materials	Stone, brick
Fate	Obsolete
Battles/wars	Siege of Paris

Fort d'Issy was one of the fortifications of the city of Paris, France, built between 1841 and 1845. It was one of six forts built to the south of the main wall around the city. The fort was placed too close to the city to be effective, and had a poor design that did not take into account recent experience of siege warfare. It was quickly silenced during the Franco-Prussian War of 1870–71. After the armistice of February 1871 the fort was defended by National Guards of the Paris Commune against the French regular army in April–May 1871. The defense was irresolute and the fort was soon occupied. Today the site of the fort is an "eco-district", an ecologically friendly residential area.

In 1814 and 1815 Paris was twice occupied by a coalition of British, Austrian, Russian and Prussian forces at the end of the Napoleonic Wars. After the restoration of the Bourbon monarchy, and particularly after the July Monarchy came to power in 1830, there was growing demand for construction of fortifications around Paris. Tension with the coalition rose during the Oriental Crisis of 1840. Prime Minister Adolphe Thiers was authorized by the cabinet in September 1840 to begin construction of the defense system, and was given funding. General Guillaume Dode de la Brunerie was appointed overall director of the program. A continuous wall would encircle the city, protected by detached forts. After debates over the plans in Parliament, a law of 3 April 1841 approved funding for the project and defined a clear zone (zone non aedificandi) around the walls. The Thiers fortifications were built between 1841 and 1845.

Fort Issy was located on the heights overlooking Issy-les-Moulineaux and Paris. It commanded the Seine. It was the furthest west of a line of six detached forts that defended the south of Paris. Each fort was large and powerful, with high escarps, large interiors and ample accommodation for their garrisons. However, they were so close to the enceinte of Paris that they served as outworks rather than independent forts. The decision about where to place the southern line of forts may have been influenced by the fact that in 1815 Field Marshal Blucher had arrived on the Issy and Vanves heights, overlooking Paris.