Porte de Monsieur's other name

The Porte de Monsieur, located on the commune of Allègre in the department Haute-Loire and region Auvergne-Rhône-Alpes, started life as a fortified city gate, serving as the main entrance to the castle of Allègre. By the 19th century, it had been transformed. It now stands as a grand public building, with a clock tower atop a gate that hides a thousand-year-old secret. The name of this gate bears the title of the lords of Allègre: 'Monsieur'. It's unclear when it was built during the reign of a specific King Louis.

Sources: Wikipedia, OpenStreetMap, Wikidata, Wikimedia Commons