Crossing the capital from its north-eastern to south-eastern sections via a moderately curved path, it links La Courneuve–8 mai 1945 in the north with Mairie d'Ivry and Villejuif–Louis Aragon in the south, while passing through important parts of central Paris.

Southbound trains terminate alternately at Villejuif - Louis Aragon and Mairie d'Ivry, diverging at Maison Blanche.

In the north, the line begins at La Courneuve in the department of Seine-Saint-Denis at the intersection of National Routes 2 and 186.

Running below National Route 2 (RN2), the line heads to the south-west, entering Paris in two single-line tunnels so as to avoid a now-unused terminal loop at Porte de la Villette.

It then descends a 4% grade below Canal Saint-Denis and then climbs back up to stop at Corentin Cariou.