The cost and the actors
The investment cost of the project is estimated at €430.8 million excluding tax at the economic conditions of January 2017. This is an estimate at the preliminary study stage, the accuracy of which is estimated to be plus or minus 10%.
This investment cost includes:
- €379.8 million for infrastructure expenditure,
- €51 million for the purchase of rolling stock.

Financing
The work
- The Hauts de Seine Departmental Council (30%)
- The Île-de-France region (49%)
- The State (21%)
Operations and rolling stock
Île-de-France Mobilités
The actors
The Hauts de Seine Departmental Council and Île-de-France Mobilités are the two project owners for the extension of the Nanterre – Rueil T1.
The local players located on the tramway route are closely involved in the construction of the project: the cities of Colombes, Nanterre and Rueil-Malmaison.
Île-de-France Mobilités
Île-de-France Mobilités imagines, organises and finances public transport for all Ile-de-France residents. At the heart of Île-de-France's transport network, Île-de-France Mobilités brings together all the players (passengers, elected officials, manufacturers, transporters, infrastructure managers,...), decides on and manages development and modernisation projects for all forms of transport, and invests and innovates to improve the service provided to passengers.
The Hauts-de-Seine Department

By facilitating travel on its territory and developing infrastructure that stimulates economic development and improves the lives of its inhabitants, the Hauts-de-Seine Department is pursuing its commitment to mobility.
The Île-de-France Region

The Region is the main funder of the development of public transport in Île-de-France. With nearly 1.5 billion euros invested each year, it works daily to improve the quality of life of Ile-de-France residents with one priority, the development of transport from suburb to suburb.
Local authorities
Local stakeholders along the tramway route are closely involved in the construction of the project.
- The city of Colombe: https://www.colombes.fr/ville-de-colombes-3.html
- The city of Nanterre: http://www.nanterre.fr/
- The city of Rueil-Malmaison: http://www.mairie-rueilmalmaison.fr/