The Sainte-Assise radio transmitter in the Seine-et-Marne agricultural plain of France operates as a military and telecommunications facility, maintaining communication with nuclear submarines while sharing its historic footprint with commercial satellite operations. Built in October 1920 under an agreement between the French state and the Compagnie générale de télégraphie sans fil, the facility was designed to free France from reliance on foreign submarine cables, according to historical documentation from the Seine-et-Marne departmental archives.
Construction and Early Broadcasting History
The site emerged as a monumental technical achievement following the 1920 convention, which tasked Compagnie Radio-France with operating a global radioelectric center. According to historical records, the initial installation featured eleven 250-meter pylons and five 180-meter masts, making it the most powerful radio transmitter in the world at the time. The infrastructure served as a diplomatic showcase where the French president hosted foreign dignitaries, including the King of Siam and the King of Romania. In November 1921, the facility hosted the first experimental French radio broadcast using a 1 kW long-wave transmitter, during which opera singer Yvonne Brothier performed multiple pieces.
Wartime Occupation and Transition to the French Navy
The agricultural estate surrounding the château transformed from an aristocratic residence into an administrative and military hub after Charles-Louis de Beauvau-Craon sold the property to Compagnie Radio France in 1922. During World War II, the German Navy occupied the Sainte-Assise transmitter to communicate with its submarine fleet, leaving the infrastructure undamaged by Allied bombing raids. Following the Liberation, the postal administration managed the site before a 1991 land transfer allocated a parcel of the estate to the French Navy (Marine Nationale), establishing an active military presence.
Modern Operations: Submarine Transmissions and Satellite Teleports
The Marine Nationale inaugurated a specialized naval transmission center at Sainte-Assise in 1998, deploying very low frequency (VLF) waves capable of penetrating seawater to maintain contact with submerged nuclear ballistic missile submarines (SNLE). Armed units of fusiliers marins currently patrol the restricted perimeter. The physical layout evolved in December 2000 when three unused 180-meter masts were dismantled. In 2009, a portion of the non-military grounds was designated as the Sainte-Assise heather moorlands regional nature reserve (réserve naturelle régionale des bruyères de Sainte-Assise).
Adjacent to the military perimeter, Globecast, a subsidiary of Orange, operates a commercial teleport featuring large satellite dishes. This secondary facility processes audio and video signals for international television and radio broadcasting, establishing a dual-use landscape where classified defense transmissions operate alongside commercial media distribution.
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