At the end of the 1920s, The Seine-et-Oise Department recorded a worrying resurgence of cases of pulmonary tuberculosis, especially in urban centres with then booming industrial and demographic growth. About 10 000 TB patients were dying per year and in 1929, an epidemic affected 700 000 people in France.
In 1930, An architectural contest was launched, won by the joint project of Édouard Crevel and Paul-Jean Decaux. Work began in April 1931 and was completed in July 1933, also the date of the opening of the sanatorium. This is a Paris construction company called Lauret which won the work. The buildings which emerged in record time and is one of the largest and most notable sanatoria built during the XXth century.
In 1936, the sanatorium, then at the height of its operation, welcomed 430 TB patients. Located in the area of armed conflict, the sanatorium in June 1940, evacuated its patients, October 1940, Pavilion Bonnefoy-Sibour was then requisitioned by the occupying military authorities to become the first “North Zone administrative internment Camp”. “Suspicious” prisoners arrested for acts of resistance, began to arrive on 5 October. A platoon of gendarmes monitored the former sanatorium, Originally planned for 150 prisoners, the camp had more than 667 in May 1941. In all, about 1500 prisoners, men and women, were detained in Aincourt, hundreds were deported to the concentration camps of Auschwitz, Buchenwald and Oranienburg-Sachsenhausen, vey few returned. The internment camp closed its doors on 15 September 1942 to be replaced by a training centre of militia Groups mobile de Reserve (GMR). In 1946, the sanatorium reopened its doors. and the infrastructure was proving increasingly inadequate in an always more demanding medical practice, the ground floor of the Pavilion Adrien Bonnefoy-Sibour, used specifically to treat tuberculosis, was closed in 1987. Pavilion Dr. Vian completely closed its doors in 1988. In 2001, it was the turn then of Pavilion Bonnefoy-Sibour to close. Only one, former children wing continues to operate, the Hospital of Vexin which became the inter-communal hospital in January 2011.
Two huge buildings Bonnefoy-Sibour, now empty, and Dr. Vian were looted and vandalised within a few years. The walls bear the scars of the battles of Paintball and the intervention of graffiti artists. The Pavilion Dr Vian bearing the scars of the different exercises for by the local fire brigade. Dr. Vian Pavilion, first, abandoned is now overgrown, heavily damaged by ingress of rainwater.
A hope remains still for the Pavilion Adrien Bonnefoy-Sibour (now fenced off) that it could be sold to developers to be rehabilitated into residential services for disabled and elderly people with 80 apartments of which 40 would be put up for sale, Originally designed to accommodate 150 patients each, these three buildings, spread out at 400 meters intervals to avoid any risk of epidemic spread, were laid on a hillside – respectively from the highest to the lowest: the Pavilions of the women, children, men Their architecture is identical and impresses with its proportions. three large buildings, 220 meters long and 12 meters wide, including three floors of rooms arranged in tiers and a rooftop terrace. The structural work is in reinforced concrete covered with initially a plaster. The construction is very neat and was performed without a crane, using scaffolding.