Mosquée de l'arsenal des galères, Historic mosque ruins in 8th arrondissement, France.

Mosquée de l'arsenal des galères is a roofless ruin of pale grey masonry in the Valbelle park, at 584 avenue du Prado. Its multi-sided plan has tall pointed-arch openings on slender colonnettes, some sealed with flat panels, and a carved cresting of repeating motifs along the flat top, above a band of small trefoil patterns. A green wire fence stands in front.

Long taken for a remnant of the early 18th-century mosque of the galley arsenal, the structure in Parc Valbelle is now dated to 1927: the industrialist Paul Rouvière had a private chapel built from the remains of a villa at 291 rue Paradis, demolished in 1926. Those stones came from the second floor of the Kiosque Bonaparte, an orientalising guinguette built by engineer Léon Cahier in 1860-1861 and destroyed in 1885. It was listed as a monument historique on 15 July 1965 under the name "mosquée".

The name recalls a mosque for Ottoman galley slaves that stood in a cemetery near Place Monthyon, not here; in 1749 an intendant described that enclosure with its mosque, well and funeral shed. The monument keeps that memory: between 1680 and 1696, 2,040 Turks rowed among 7,970 galley oarsmen of France.

The monument is in deteriorated condition and surrounded by security barriers that limit direct access to the site. Further information about its protection status and history can be found at the Médiathèque du Patrimoine.

Recent research suggests the structure may actually be a private chapel built in 1927 using materials from an existing villa, challenging traditional beliefs about its original purpose. This discovery changes what historians thought they knew about the building's true nature and age.