This entrance to the town, the only way out from the south, is known as the Porte d'Ardenne. This side of the fortress has always been vulnerable and often invaded.All that remains of the old defences are the deep cuts in which the gates were fixed.The castle that can be seen at the top of the main square is in fact a recent construction, despite its majestic facade with its countless details. Built by Jean Poswick in 1910, it is set at right angles to the square. Still a private house, it is undoubtedly one of the city's jewels.On the other side of the Porte d'Ardenne, near the ramparts, the prisons were built from 1753 onwards. In the Middle Ages, these were located in the castle. Around 1685, two unhealthy cellars were used as prisons: one under the town hall, the other at the lower gate.