T1

Line T1 currently connects Asnières-sur-Seine and Gennevilliers to Noisy-le-Sec, running almost parallel to the Paris city's northern limit. It opened in 1992 from Saint Denis's RER station to the Bobigny–Pablo Picasso Paris Métro station, where the prefecture offices of the Seine-Saint-Denis department^[12] are located. The eastern extension from Bobigny to Noisy-le-Sec was completed in 2003, while the western extension to Asnières-sur-Seine and Gennevilliers, connecting to western branch of Paris Métro Line 13, opened in 2012. A continuation towards Nanterre is planned on the western side, while another one towards Montreuil, then to the Val de Fontenay RER station is also planned on the eastern side of the line.

T2

Line T2 (Trans Val-de-Seine) connects the bridge of Bezons (Pont de Bezons) to the Porte de Versailles Paris Métro station (near Paris's main exhibit grounds) via La Défense and Issy-les-Moulineaux business districts. It opened in 1997 between La Défense and Issy–Val de Seine stations, exploiting a former SNCF line, the Moulineaux Line, which closed to regular train traffic in 1993. Tram line T2 was first extended south in 2009, from Issy–Val de Seine station to the Porte de Versailles, then north in 2012 from La Défense to the Pont de Bezons.

T3a and T3b

Line T3 (Tramway des Maréchaux) is the first modern tramway line to actually enter Paris city itself. It is divided into two sections, called T3a and T3b, separated at the Porte de Vincennes stop in order not to cut the road traffic there, despite rail and electrical infrastructure being present and operational. The line bears its name as it follows the Boulevards of the Marshals, a series of boulevards that encircle Paris along the route of the former Thiers Wall, built from 1841 to 1844. The boulevards are, with three exceptions, all named from Napoleon's First Empire marshals (maréchaux).

T3a connects the Pont du Garigliano–Hôpital européen Georges-Pompidou RER station in the southwestern part of the 15th arrondissement, with the Porte de Vincennes in the northeastern corner of the 12th arrondissement. T3b connects Porte de Vincennes with the Porte de la Chapelle Métro station in the 18th arrondissement, then to the Porte d'Asnières (17th arrondissement) since 24 November 2018.^[13] An extension westward towards the Porte Dauphine (16th arrondissement) is planned, but currently halted by western extension of the RER E line.

T4

Line T4 is an 8-kilometre (5.0 mi), 11-stop^[8] forked tram-train line, connecting the Bondy and Aulnay-sous-Bois RER stations on top of a former train track similar to Line 2. It opened on 18 November 2006. Unlike the other tramways in Île-de-France, Line T4 is operated by the SNCF. A new branch of this tram-train line, heading east towards Montfermeil, opened in 2020.

T5

Tramway T5^[14] is a Translohr tram-on-tyres^[15] running along a mainly segregated "track" on the busy Route Nationale 1 (similar to the systems in Nancy or Caen) where it replaces the former bus lines 168 and 268. The 6.6-kilometre (4.1 mi) route^[15] serves 16 stops^[15] between Saint-Denis, Pierrefitte-sur-Seine, Sarcelles and Garges-lès-Gonesse. It has an interchange with T1 at its southernmost terminus, Marché de Saint-Denis, and with RER D at its northernmost terminus, the Garges-Sarcelles RER station.^[16] Line T5 opened in July 2013.^[17]

T6

Tramway Line 6 is a 14-kilometre (8.7 mi) Translohr tram-on-tyres line serving 21 stations, from the Châtillon–Montrouge Métro station (the southern terminus of Paris Métro Line 13) to the Viroflay-Rive-Droite Transilien station through Vélizy-Villacoublay. The 1.6 kilometres (0.99 mi) westernmost part of the line (through Viroflay), is underground, in a single tunnel grossing the town from south to north and including the two final stops, each under the two train stations the city has, Rive-Gauche (Lines C and N) and Rive-Droite (Line L). The majority of the current line opened in 2014, with said tunnel section opening in 2016. It replaced bus line 295, that became overcrowded and too slow for proper use, as well as multiple of the former Kéolis lines operating across Vélizy.

T7

Tramway Line 7 is an 11.2-kilometre (7.0 mi) route serving 18 stations^[7] between Villejuif–Louis Aragon (southwestern terminus of Paris Métro Line 7) and Athis-Mons, via Rungis International Market and Orly Airport. It opened in 2013^[18] in order to both allow a supplemental rail service from Paris to Orly Airport and replace bus line 285, which had also become overcrowded on its now supplemented part. The remaining part of said bus line is also planned to be replaced by the upcoming southern extension of Tram Line 7 towards the Juvisy-sur-Orge train station.

T8

Formerly known as Tram'y due to its opening-day Y-shape (while T4 got its Y-shape after its initial opening), this 8.46-kilometre (5.26 mi) tram line goes from the Saint-Denis–Porte de Paris Métro station to Épinay-sur-Seine — Orgemont, with a branch to the university campus of Villetaneuse, where it connects to the more recent T11 Express Line. An extension is also planned south, to Paris itself, at the Rosa Parks RER station. Construction of the line began in 2010; service began in 2014. The southern extension's opening date has not yet been set.^[18]

T9

T9 is a tram line that runs between the Porte de Choisy Paris Métro station and the centre of Orly with a length of 10.3 km (6.4 mi) and 19 stops. Despite what its indice digit suggests, it opened after Tram Line 11 express. An extension south towards Orly is planned.

T10

T10 is a tram line from La Croix de Berny station in Antony to Clamart in the southwestern suburbs of Paris. It opened in 2023 with a length of 6.8 km (4.2 mi) and thirteen stops.

T11 Express

First "Express" tram line of the Parisian network — due to reusing the long-closed Grande Ceinture train line with only a handful of stations — Line T11 Express serves as the first of three lines to cover the former Grande Ceinture rail line and offers eventually a second circular railroad service around Paris, something the Paris public transport system sorely lacked for decades.

Line T11 Express opened in 2017 between the Épinay-sur-Seine and Le Bourget RER stations, the middle part of its expected full route between Sartrouville and Noisy-le-Sec RER stations. This full route project would make T11 the first tram line to connect every RER line currently in service.

T12 Express

T12 Express is a tram-train line between Évry-Courcouronnes station (RER D) and Massy-Palaiseau station (RER B and C) via Épinay-sur-Orge station (RER C), with a length of 20 km (12 mi) and 16 stops. This line uses the stretch of railway between Épinay and Massy formerly served by RER C. An extension of T12 further northwest, towards Versailles-Chantiers, is planned and would take over Transilien line V between Massy and Versailles as well if entered.^[19]

T13 Express

T13 Express is a tram-train line between Saint-Germain-en-Laye and Saint-Cyr-l'École train stations (RER C and Transilien lines N and U) via the westernmost point of the gardens of Versailles with a length of 18.8 km (11.7 mi) and 11 stops. It opened on 6 July 2022. No extensions are planned.