Paris Métro Line 8 is one of the sixteen lines of the Paris Métro. It connects Balard in the southwestern part of Paris to Pointe du Lac station in the southeastern suburbs, following a parabolic route on the Rive Droite of the Seine. The last line of the original 1898 Paris Métro plan, which opened in July 1913, it was initially intended to link Porte d'Auteuil and Opéra. With 105.5 million travellers in 2017, it is the network's eighth busiest line; at 23.4 km (14.5 mi) in length, it is also the second longest Métro Line after Line 13, and the longest fully straight line, as line 13 has branches. Along with Line 7, it serves the most stations of any line on the network, at 38. Line 8 interchanges with all but three other Métro lines.

The Paris Métro, operated by the Régie autonome des transports parisiens (RATP), is a rapid transit system in the Paris metropolitan area, France. 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, numbered 1 to 14, with two lines, Line 3bis and Line 7bis, named because they used to be part 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.