The Paris Métro , operated by the Régie autonome des transports parisiens , 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 entrances influenced by Art Nouveau. The system is 226.9 kilometres 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, 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.