Château de Marracq, Historic castle ruins in Bayonne, France.

Château de Marracq is a castle ruin in Bayonne consisting of two substantial stone walls that rise from the ground, marking where a fortress once stood. The remaining structures show traces of the 18th-century construction, with weathered surfaces revealing layers of history.

Marie-Anne de Neubourg, exiled queen of Spain, built the château at the start of the 18th century but never lived there, preferring her residence at Saint-Michel. Napoleon bought it on 19 May 1808 from the Marqfoy brothers and made it an imperial palace. The Bayonne abdications of the Spanish Bourbons were signed there in 1808. After 1823 the army occupied it, and a fire destroyed it in 1825.

The name Marracq comes from the Marqfoy brothers, Aaron (1758–1827) and Abraham (1773–1840), who owned the estate before selling it to Napoleon on 19 May 1808. The site is now owned by the city of Bayonne and is used as a historical monument; the Collège Marracq stands to its north.

The ruins are located at Avenue Interne Jacques Loeb in Bayonne and can be reached easily on foot from the city center. Ongoing preservation work means the site may have restricted access at certain times, so checking conditions beforehand is helpful.

Napoleon bought Marracq on 19 May 1808 from the brothers Aaron and Abraham Marqfoy, paying from his personal funds, and made it one of his imperial palaces. He preferred it to the Château-Vieux during his stay in Bayonne. The abdications of the Spanish Bourbons in favour of Napoleon were signed here, and he placed his brother Joseph on the Spanish throne.