The intermediate “Quincampe” turret built right up against the rampart is located halfway between two larger towers, the Madeleine Tower and another now integrated into the housing near the North Postern.
At the foot of the rampart, barred openings, created at a later date, give access to the «inner covered way», a ring of underground tunnels around the fortified town : over time during alerts these connected the shelters and the rooms provided for the soldiers and the reserves.
By taking the stairs to reach the threshold of the Castrum, the fortified part of the town, one can see the thickness of the wall, illustrating once again the strength of this rampart. The stones, like those of the town monuments, are made of limestone from Château-Landon. Very hard and frost-resistant, it has been chosen for the construction of many Parisian monuments.