Paris Métro Line 5 is one of the 16 Metro lines built in Paris, France. It crosses the east of Paris from Bobigny – Pablo Picasso to Place d'Italie. It is the eighth-busiest line on the network.

Line 4 is one of the sixteen lines of the Paris Métro rapid transit system and one of its three fully automated lines. Situated mostly within the boundaries of the City of Paris, it connects Porte de Clignancourt in the north and Bagneux-Lucie Aubrac in the south, travelling across the heart of the city. 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 express lines. It also serves three of the Paris Railway stations, Gare du Nord, Gare de l'Est, and Gare Montparnasse. It is the second-busiest Métro line after Line 1, carrying over 154 million passengers in 2004.