What is the difference between the Paris meridian and the current Prime Meridian?

The prime meridian, also known as the "prime meridian" or "zero meridian", is the starting longitude for calculating longitude on the earth. The formulation and use of the prime meridian evolved through changes. (For details, see: http://202.205.177.137/science/dili/9/18.htm)

The Paris meridian is the longitude passing through Paris, the capital of France. 1

In 1799, French scientists Delambre and Mechamp used the length of the Paris meridian as the benchmark and set one forty-millionth of the total length of the Paris meridian as 1 meter. In 1875, representatives from 17 countries in the world met in Paris on the issue of the international metric system. From then on, the international unit of length was set as the meter.