Château de Costaérès

Château de Costaérès in Trégastel, France, is a late 19th-century country house built between 1892 and 1896 in a neo-medieval, neo-Gothic manner for the engineer and mathematician Bruno Abakanowicz. Erected on a roughly one-hectare islet, the house quickly became notable not only for its romantic architecture but also for its role as a gathering place for artists and émigrés, and for its association with literary creation in the early 20th century.

Bruno Abakanowicz bought the islet in late summer 1892, paying a small sum per square metre, and set about building a manor suited to seaside life. Construction continued through 1896; the finished interiors incorporated timber taken from the three-masted ship Maurice, which came ashore during the winter of 1896. After Abakanowicz’s death around 1900, his daughter Sofia Poray completed outstanding work on the house and added a rear west wing that enlarged the living quarters.

At the turn of the century the house became a meeting point for Polish émigrés and visiting artists. Painters and writers spent time at Costaérès, and while resident there Henryk Sienkiewicz wrote the novel Quo Vadis. Those years established the house as a small cultural salon linked to Polish expatriate networks in France.

During the Second World War the German army requisitioned the building and used it as a compact military post, an occupation that produced some harm to the interior. In 1988 the property passed into the hands of the German actor and comedian Dieter Hallervorden, who used it as a secondary residence. On 6 September 1990 a fire that followed roofing work destroyed parts of the interior; those damaged spaces were later repaired. The islet and its house form part of the protected coastal area known as Côte de granit rose–Sept-Îles. In 2024 the château served as a filming location for the television series La Maison, and the property was placed on the market for sale from 2025.