The project involves constructing a 6.5km branch off the initial Bondy - Aulnay-sous-Bois section from a junction at Gargan. The branch will have 11 stations, including an interchange with the future Grand Paris Express metro Line 16 at Clichy-Montfermeil. Daily ridership is forecast to be around 37,000, and around 30% of journeys will be through trips from Line 16.

The line will operate between 04.30 and 01.20 with services running at six-minute intervals between 06.00 and 20.00. The journey time between Bondy and Montfermeil will be around 30 minutes.

Services will be operated by Line T4’s existing fleet of Siemens Avanto tram-trains and 15 new Alstom Citadis Dualis vehicles, which were ordered by French National Railways (SNCF) earlier this year.

The region of Ile-de-France is providing 49% of funding for the €270m project, with 37% coming from the French state and 14% from SNCF. In addition, Ile-de-France transport authority Stif is providing €100m for the new tram-trains and a new depot to maintain the fleet.

Commissioning of the extension is scheduled for 2019.