Gilded reception rooms, a huge ballroom, offices, and, several meters below, a heavy reinforced door. The Paris City Hall hides in its basements a rather unexpected remnant of the interwar period: a bunker built in 1937, at a time when the prospect of a new European conflict was becoming increasingly serious.
To reach it, you must venture into the normally inaccessible parts of the building, take a passageway connecting its two wings, and then descend to level -1. Behind an imposing reinforced door lies this former civil defense shelter, now decommissioned and converted into a vast storage area.
A bunker built in the wake of the trauma of 1918
Its construction can be traced in part to another episode in Parisian history. On March 29, 1918, in the midst of World War I, a German shell fired from a very long distance struck the Church of Saint-Gervais-Saint-Protais, located just behind City Hall. Part of the vault collapsed in the middle of the Good Friday service, killing 91 people.
As international tensions rose in the 1930s, French authorities were determined not to face such a catastrophe unprepared again. Paris was soon dotted with shelters: beginning in 1935, the capital had 250 gas-tight shelters, installed primarily beneath administrative buildings and strategic infrastructure. Ironically, it was never used for its original purpose. The building weathered the Occupation and then the fighting during the Liberation without the shelter ever having to fulfill the role for which it was built.
The site still bears several traces of that era. The City of Paris notably highlights its former pneumatic tube system, parts of which remain visible on the ceiling. This network of tubes was once used to quickly send messages between City Hall, its annexes, and various Parisian government offices. The Parisian system, developed beginning in 1868, was not permanently discontinued until 1984.
Unlike some shelters that are opened exceptionally during Heritage Days, the one at City Hall is not open to the public. It still serves primarily as a storage area, behind its reinforced door.
Location: Paris City Hall, Place de l’Hôtel-de-Ville, 75004 Paris