A symbol of the city, it is known for its density within the capital's territorial limits, uniform architecture and historical entrances influenced by Art Nouveau.

[17] CMP was known as "Le Métropolitain", which quickly became abbreviated to Métro, which became a common designation and brand name for rapid transit systems in France and in many cities elsewhere.

Prior to 1845, the urban transport network consisted primarily of a large number of omnibus lines, consolidated by the French government into a regulated system with fixed and unconflicting routes and schedules.

[20] The first concrete proposal for an urban rail system in Paris was put forward by civil engineer Florence de Kérizouet.

[21] In 1855, civil engineers Edouard Brame and Eugène Flachat proposed an underground freight urban railway, due to the high rate of accidents on surface rail lines.

[21] On 19 November 1871 the General Council of the Seine commissioned a team of 40 engineers to plan an urban rail network.

[25] The issue was finally settled when the Minister of Public Works begrudgingly recognised the city's right to build a local system on 22 November 1895, and by the city's secret designing of the trains and tunnels to be too narrow for mainline trains, while adopting standard gauge as a compromise with the state.

NS distinguished itself from its competitor with the high-quality decoration of its stations, the trains' extreme comfort and pretty lighting.

It extended north in encompassing the already-built portion between Invalides and Duroc, initially planned as part of the inner circular.

[citation needed] On 23 March 1948, the CMP (the underground) and the STCRP (bus and tramways) merged to form the RATP, which still operates the Métro.

Outdated technology limited the number of trains, which led the RATP to stop extending lines and concentrate on modernisation.

The MP 51 prototype was built, testing both rubber-tyred metro and basic automatic driving on the voie navette.

[citation needed] The short distance between Métro stations slowed the network and made it unprofitable to build extensions.

During construction in 1900, a minimum radius of curvature of just 75 metres (246 ft) was imposed, but even this low standard was not adhered to at Bastille and Notre-Dame-de-Lorette.

[26] In contrast to many other historical metro systems (such as New York, Madrid, London, and Boston), all lines have tunnels and operate trains with the same dimensions.

Five Paris Métro Lines (1, 4, 6, 11 and 14) run on a rubber tire system developed by the RATP in the 1950s, exported to the Montreal, Santiago, Mexico City and Lausanne metro.

The last train, often called the "balai" (broom) because it sweeps up remaining passengers, arrives at the terminus at 1:15 a.m., except on Fridays (since 7 December 2007),[39] Saturdays and on nights before a holiday, when the service ends at 2:15 a.m. On New Year's Eve, Fête de la Musique, Nuit Blanche and other events, some stations on Lines 1, 4, 6, 9 and 14 remain open all night.

[49][50] The Law on Equal Rights and Opportunities, Participation and Citizenship of Persons with Disabilities of 2005 [fr] does not require the Métro to be made accessible.

The system is complemented by the RER, which extends farther out into the suburbs and functions as an express network for the city and its surroundings.

The specifications established in 1900 required a very low minimum curve radius by railway standards, but even this was often not fully respected, for example near Bastille and Notre Dame de Lorette.

All other termini have trains continue a certain distance beyond the terminal, before proceeding back to the station on a different platform headed the other way.

Some stations are single-track, either due to difficult terrain (Saint-Georges), a narrow street above (Liège) or track loops (Église d'Auteuil).

One of the three platforms at Porte des Lilas station is on a currently unused section of track, often used as a backdrop in films.

Standard vaulted stations are lined by small white earthenware tiles, chosen because of the poor efficiency of early twentieth century electric lighting.

From the outset walls have been used for advertising; posters in early stations are framed by coloured tiles with the name of the original operator (CMP or Nord Sud).

The first renovations took place after the Second World War, when the installation of fluorescent lighting revealed the poor state of the original tiling.

A handful of entrances have original architecture (Saint-Lazare); a number are integrated into residential or standalone buildings (Pelleport).

[69][66] In addition to the projects already under construction or currently being actively studied, there have also been proposals for: The Métro has a cultural significance in the arts that goes well beyond Paris.

The station entrance kiosks, designed by Hector Guimard, fostered Art Nouveau building style (once widely known as "le style Métro");[72] however, some French commentators criticised the Guimard station kiosks, including their green colour and sign lettering, as difficult to read.

The Japanese adopted rubber-tired metros (with their own technology and manufacturing firms) to systems in Kobe, Sapporo, as well as parts of Tokyo.