Château Rothschild, château in Boulogne-Billancourt, France

Château Rothschild is a long stone building in Boulogne-Billancourt, rebuilt 1855–1861 by architect Joseph-Armand Berthelin in the Louis XIV style after the model of the Château de Clagny. Its grey facade has a row of oval and circular dormer windows, many boarded or dark-glazed, with graffiti on the stone between them; below, tall rectangular openings are sealed with pale panels, and a recessed colonnade of columns stands near the centre. Seven chimneys, some pale brick and some stone, line the dark roof, whose left end has a green-painted section, and a dense hedge runs along the base.

The mansion was built between 1855 and 1861 by architect Joseph-Armand Berthelin for James de Rothschild. It was constructed on the site of an earlier residence that had existed since the early 1700s.

James de Rothschild's receptions drew guests such as President Adolphe Thiers, Georges Clemenceau, Heine, Rossini and Chopin. Edmond de Rothschild, taken by Japanese plants at the 1900 Exposition Universelle, hired the Tokyo horticulturist Hatta, who created a Japanese garden with a pagoda and tea house before 1925.

The château itself stands abandoned and vandalised, so it cannot be entered; the 15 hectares of the former park that survive are laid out as a public park. The rest of the grounds have been built over or lie derelict. Restoration by the owner Novaxia was announced with work due to begin in 2020.

After the 1900 World's Fair, Edmond de Rothschild added a Japanese garden with rare plants and specimen trees to the grounds. This garden reflects the fascination wealthy Europeans had with Eastern garden design during the Belle Époque era.