A one-bedroom apartment inside Hector Guimard’s Castel Béranger—the architect best known for Paris’s iconic Art Nouveau Métro entrances—pairs original period details with a design-led renovation by its owner.

The château dates to the 16th century and was once held by one of France’s oldest noble families, while the wider estate carries a permit for 17 villas within its forested grounds.

For £5.5 million, you can buy 1,110 acres of Scottish wilderness—and a castle to restore, built by an Antarctic explorer whose architect sank with the Titanic.