Bygget av tunnelbanan i Paris 1899-1911. "Le Métro de Paris".

The history of the subway, or underground railway, dates back to the 19th century. The first underground railway was the Metropolitan Railway in London, which opened in 1863. It was proposed for London by Charles Pearson, a city solicitor, as part of a city-improvement plan shortly after the opening of the Thames Tunnel in 1843. The subway quickly became a popular mode of transportation in urban areas, as it allowed people to travel quickly and efficiently through the city. Over time, many cities around the world built their own subway systems, and today, subway trains are a common sight in many major cities. The technology used in subway systems has evolved over time, and modern trains are faster and more efficient than ever before.

A symbol of the city, it is known for its density within the capital's territorial limits, uniform architecture and unique historical entrances influenced by Art Nouveau. The system is 226.9 kilometres (141.0 mi) long, mostly underground. It has 308 stations of which 64 have transfers between lines. There are 16 lines (with an additional four under construction), numbered 1 to 14, with two lines, 3bis and 7bis, named because they started out as branches of Line 3 and Line 7, respectively. Line 1, Line 4 and Line 14 are automated. Lines are identified on maps by number and colour, with the direction of travel indicated by the terminus.