On June 19, 1940, when German troops were reported in the eastern department, the French army was trying to slow their advance by blowing up the bridges over the Indre, including Chambourg. Between June 22, 1940 and 28 February 1943, the demarcation line ran north–south in the town of Le Château-le-Sec, bordering Chambourg-sur-Indre on the west: Chambourg-sur-Indre was in zone libre (unoccupied territory), but only a few kilometers from the line; the municipality was rejoined on 28 February 1943 to the prefecture of Indre. As early as June 1940, the prefect of Indre replaced the elected mayor by a special delegation of four members who served until October 1944. In the last decade of August 1944, German troops gradually withdrew to the north and east of the department after Loches was recaptured they had to leave for a few days. Their headquarters was temporarily set up in St. Valentin, a hamlet of Chambourg near the municipal boundary with Loches.