The adoption of the bill, which creates a legal basis for the provisions of an agreement signed by the two countries in February 2015, clears the way for tendering to begin this year and construction is due to start in 2018.
The bilateral agreement was formally adopted by both the French National Assembly and the Italian Chamber of Deputies in December.
The 140km line will have 87km of tunnels including a 57km twin-bore base tunnel between St Jean de Maurienne, France, and Chiomonte in Italy. The cross-border section extends for 18.1km on the Italian side, 12.5km of which will be in the base tunnel. Beyond the Italian portal, there will be a 3km link to the existing line at Bussoleno, including a 2.1km tunnel and a new station at Susa.
Implementation of the project is being managed by Euralpine Tunnel Lyon - Turin (TELT), a 50:50 joint venture between Italian State Railways (FS) and the French state.
The line is expected to open in 2028 or 2029, reducing Lyon - Turin journey times from 3h 30min to 1h 47min.