Lacoste is a commune in the Vaucluse department in the Provence-Alpes-Côte d'Azur region in southeastern France.
Lacoste is a picturesque old mountain village overlooking the village of Bonnieux and the Grand Luberon Mountains to the east, and flanked by the Vaucluse to the north and the Petit Luberon to the south.
Lacoste is best known for its most notorious resident, Donatien Alphonse Francois comte de Sade, the Marquis de Sade, who in the 18th century lived in the castle, Château de Lacoste, overlooking the village. Following a series of incidents involving local women and the police, the Marquis fled the country but was eventually imprisoned. His castle was partially destroyed in an uprising in 1779 and was later looted and plundered by locals. It is now owned by fashion designer Pierre Cardin, who has partially restored it and holds cultural events there.
During the first half of the 19th century the village saw a brief time of agricultural and economic prosperity from the Roman limestone quarries, but soon hit a slump in the second half of the century and a large portion of the upper village of Lacoste fell into disrepair and ruins.
During World War II, the French Resistance took their foothold in the steep Luberon Mountains around Lacoste, and trenches and barbed wire still exist in the forested area in the valley, where resistance fighters prepared to square off with German troops.