Why are all distances measured from the Notre Dame?

Question

i said it in da question

Answer 1

Its a common practice to measure distances from a central point, usually in a county's capitol, and originated at least as early as ancient Rome's  Milliarium Aureum ("Golden Milestone") from which all distances in the empire were measured.

As a practical matter it serves to unify a country by directing the attention of all inhabitants to the center of authority.

In France this is fittingly in the plaza in front of Notre Dame which is the site from which the power of Paris emanated in its earliest days when Paris was founded on the Ile de la Cite.