The boulevards are, with three exceptions, named for Napoleon's First Empire marshals (maréchaux); they were transformed by redevelopment works carried out during the two-and-a-half-year construction of the line, which opened on 16 December 2006 under the designation T3.

The line initially ran in its own section of these boulevards' roadway between the 15th and 13th arrondissements, allowing it to connect the Pont du Garigliano and Porte d'Ivry in an average of 26 minutes.

It carried 25 million passengers in its first year of operation, averaging 100,000 on weekdays and 70,000 on weekends; numbers have steadily increased ever since.

[1] A further extension with seven stops towards Porte Dauphine in the 16th arrondissement just east of the Bois de Boulogne started service on 5 April 2024.

[4] The Little Ring Line (Ligne de la Petite Ceinture) was constructed in order to link the major rail supply routes within the Thiers Fortifications that surrounded Paris.

The line was opened in sections between 1852 and 1869, reaching a total length of 32 km (20 mi) and encircling Paris within the boulevards des Maréchaux.

The section of the Ligne d'Auteuil between Pereire-Levallois and Avenue Henri-Martin, however, was integrated with RER C of the commuter rail network (Réseau Express Régional).