During World War I, 187 men of Janzé were killed in battle. A war memorial () in their honor was erected in 1920. Later, 20 names of soldiers fallen during World War II were added, along with five names from the Indochina Wars and the Algerian War. Janzé was occupied by the Germans during World War II from 18 June 1940 until 3 August 1944, when the town was liberated by the American army.