The Petite Ceinture railway circling through the city of Paris served urban travelers from 1862 to 1934 before being abandoned.
Predating the Paris Métro, the “little belt” railroad connected the main train stations and provided needed fortification for the city. Construction was started in 1852 under the Empire of Napoléon III and Baron Haussmann, the influential civic planner. The 20th century sprawl of Paris beyond the Petite Ceinture and the success of the Métro eventually made the circular railway obsolete.
Certain stretches are now overgrown with over 200 species of flora and fauna, vibrant with colorful flowers in the spring months and greenery against vivid graffiti and street art. Bridges, tunnels, and the original tracks remain mostly untouched, hidden just beyond the streets and neighborhoods of the outer arrondissements.
A section in the 16th arrondissement was incorporated into the RER regional network system in 1988, and in 2008 a section between the Porte d’Auteuil and the Gare de la Muette was opened to pedestrians as a nature trail. Several other sections are now open to the public, in the 16th, the 15th, and the 12th arrondissements. Although the remaining parts are closed, their accessibility from nine arrondissements makes it popular with urban explorers. The catacombs of Paris even have their easiest entry point from one of the tunnels on the Petite Ceinture.
A good way to see some old train stations is to enter via Villa du Bel Air and exit at the old Gare de Charonne before the tunnel.
The majority of the tracks are still owned and managed by the SNCF and are still in working order, notably the sections that link the Gare de Bercy with the Gare de Nord and Gare de l’Est in the east of the city.
City officials in cooperation with SNCF have begun a program to open up parts of the Petite Ceinture to the communities it runs through. The project is a long term undertaking but has already seen several parts turned into walkways and parks, while still preserving the biodiversity and heritage of the sites. A few dozen kilometers are reserved for pedestrians at the moment. However, keep in mind that some sections are not safe, thus it’s better to walk with a company.