Paris Metro Line 4

Line 4
MP 14 at Cité station.
Overview
Termini	Porte de Clignancourt Bagneux-Lucie Aubrac
Connecting lines
Stations	29
Service
System	Paris Métro
Operator	RATP
Rolling stock	MP 89CA (21 trains in operation as of 5 June 2023) MP 05 (11 trains in operation as of 10 February 2023) MP 14 (20 trains in operation as of 18 March 2025)
Ridership	167,000,000 (avg. per year) 2nd/16
History
Opened	21 April 1908 (21 April 1908)
Technical
Line length	13.9 km (8.6 mi)
Track gauge	1,435 mm (4 ft 8+1⁄2 in) standard gauge between roll ways
Electrification	750 V DC, guide bars on either side of the track
Conduction system	Automated (SAET)
Route map Saint-Ouen shops Seine-Saint-Denis Paris Porte de Clignancourt Simplon Marcadet–Poissonniers Château Rouge Barbès–Rochechouart to La Plaine–Stade de France to Stade de France–Saint-Denis Gare du Nord Gare de l'Est Château d'Eau Strasbourg–Saint-Denis Réaumur–Sébastopol Étienne Marcel Les Halles Châtelet–Les Halles (RER) Châtelet Seine Cité Seine Saint-Michel Saint-Michel–Notre-Dame (RER) Odéon Saint-Germain-des-Prés Saint-Sulpice Saint-Placide Montparnasse–Bienvenüe Vavin Raspail Denfert-Rochereau to Cité Universitaire Mouton-Duvernet Alésia Porte d'Orléans Original terminus Paris Hauts-de-Seine Mairie de Montrouge Barbara Bagneux–Lucie Aubrac future

Line 4 (French pronunciation: [liɲᵊ katʁᵊ]) is one of the sixteen currently opened lines of the Paris Métro, as well as one of its three fully automated lines. It connects Porte de Clignancourt in the north of Paris, to Bagneux-Lucie Aubrac in the eponymous southern suburban city, on a north-south axis across the French Capital. Held within the boundaries of the City of Paris for over a century – until its southern terminus was changed from Porte d'Orléans to Mairie de Montrouge in 2013 – the line was sometimes referred to as the Clignancourt – Orléans Line. At 13.9 km (8.6 mi) in length, it connects with all Paris Métro lines apart from the very short 3bis and 7bis branch lines, as well as with all 5 RER train lines. It also serves three of the Paris Railway stations, Gare du Nord, Gare de l'Est, and Gare Montparnasse.

Line 4 was the first line to connect to the south side of the River Seine, through an underwater tunnel built between 1905 and 1907. Line 4 long ran the longest-serving MP 59 rubber trains, which used rheostats to dissipate the braking power through resistance, making line 4 the hottest line in the system. Those trains were withdrawn from service on Line 4 during the course of 2011 and 2012 after 45 years (with some being in service for 50 years), yet remained another 12 years on in service on Line 11. On Line 4, they were replaced by the MP 89 CC stock transferred from Line 1, right after its automation.

In 2013, Line 4 was extended for the first time since its initial construction, into the southern suburbs of Montrouge. The line was further extended to Bagneux–Lucie Aubrac in 2022, connecting to the future Grand Paris Express. The line has been retrofitted for full automation, with the first automated trains commencing service on 12 September 2022.