The Aincourt sanatorium was a cure center specializing in the treatment of pulmonary tuberculosis ( phthisis ) located in the village of Aincourt (department of Val-d'Oise ) in France .

The sanatorium , currently located in the French Vexin Regional Natural Park , was built by architects Édouard Crevel and Paul Decaux , between 1931 and 1933 . It is one of the largest sets of this class built in xx th century . It was also a concentration camp between 1940 and 1942 .