The Île de la Cité is an island in the river Seine in the center of Paris. In the 4th century, it was the site of the fortress of the Roman governor. In 508 Clovis I, the first King of the Franks, established his palace on the island. In the 12th century it became an important religious center, the home of Notre-Dame cathedral, and the royal chapel of Sainte-Chapelle, as well as the city's first hospital: the Hôtel-Dieu. It is also the site of the city's oldest surviving bridge, the Pont Neuf.
With the departure of the French kings to the Louvre Palace and then to the Palace of Versailles, the island became France's judicial centre. In 1302 it hosted the first meeting of the Parliament of Paris and was later the site of the trials of aristocrats in the French Revolution.
Wikipedia https://en.wikipedia.org/wiki/Île_de_la_Cité
Coordinates 48°51'16.906" N 2°20'49.812" E