Notre-Dame

Facing the main square of the Notre-Dame is the zero kilometer - the point from which distances are measured on maps and signposts.

An excerpt from the article 18 facts about Notre-Dame
The Paris one is made of bronze and has an octagonal shape with an engraved compass rose. The site was chosen by King Louis XV in 1769 and marked with a milestone on October 10, 1786. Then, on October 10, 1924, it appeared in a new guise, precisely 138 years later. According to legend, anyone who stands on it will return to Paris again someday.