Chateau de Carnelle is located within the grounds of a large hospital complex, now completely disused. The Hospital Carnelle is located within an area of forest; the land was donated by the monks of Saint-Denis by Charles V. The land changed hands many times over the centuries. The last land owner was the Duke of Massa who rebuilt the castle in 1880. The castle design is a copy of Château de Maison-Laffite in the Mansard style. Along with the castle, the buildings also included a chapel, a theatre, an orangery, a rotunda and a common. The park also includes several greenhouses, and is home to over 100 different species of trees, many of which are rare.
The Duke donated his estate to the city of Paris and the castle was converted into a sanatorium and the first patients were admitted in 1930. New buildings were added over the years including a surgery and a ward comprising over 500 beds. The discovery of drugs to treat tuberculosis led to a dramatic decline in the number of admissions to the hospital.
Foreseeing this recession, in 1966 the medical director Dr. Kerambrun undertook a project to convert the sanatorium into a dietary and guidance service. Opening in 1970 the facility had 60 individual rooms and was operational until 1992. 
A renovation project is currently taking place to restore the building and put it back into use.
Original Article on : https://www.bcd-urbex.com/chateau-de-carnelle-france/