In every city in the world there must be the Zero Kilometer that marks the first measurement, just like the Point Zero that’s located just right 10 steps in front of Notre Dame!
Point Zero marks the spot from which all road distances are measured in France. This marker was first placed there April 22, 1769. The current star/stone was place in the pavement in 1924. Notre Dame itself is at Ile de la Cite, which was the first settlement and starting point of Paris, forming Notre Dame, Sainte-Chapelle, Palais de Justice, La Conciergerie, and also Hotel Dieu!
Make a wish there, or just wish you’d be back to Paris, trust me, it worked for me!:p