At the beginning of the Great War, Cambrai was far from the Western Front; but as the fighting progressed, the town found itself behind the Hindenburg Line where it became an important staging post for the German Army. Appreciative of the peaceful atmosphere in the town, war-weary soldiers returning from the Front nicknamed the town the 'sanatorium of Flanders'. The German author Ernst Jünger witnessed the launch of the British offensive in late 1917 which failed to take the town, despite the heavy use of a new kind of weapon: the tank.
Cambrai was eventually liberated on 8th October 1918 when the Canadians, encountering little resistance, took the town. The month before their withdrawal, the Germans evacuated the town and set fire to its centre. Symbolic of the destruction the Germans wreaked in the town, the Jacks which struck the hour on the chimes of the town hall clock (affectionately known as Martin and Martine) were wrenched from their perch and thrown to the ground.
In the aftermath of the war it was clear that the town centre had to be rebuilt because more than half the houses had been destroyed and the town hall was greatly damaged. A committee comprising elected representatives, engineers, architects and artists decided to completely rethink the area and entrusted the task to architect Pierre Leprince-Ringuet who drew up a new and modern layout for the centre. Around the town hall, which he had rebuilt in its original 18th-century style, Leprince-Ringuet grouped together the various different activities of the town: the court, the chamber of commerce and the post office were placed around République Square; the prefectural offices were rebuilt on Fénelon Square; and the shopping district was concentrated around Armes Square, in Flemish-style buildings. In all, a multitude of squares and streets were built and enlarged to facilitate the movement of traffic and make Cambrai the modern but characterful town it is today.