The segment is a priority infrastructure project of the European Union (EU), as the Turin–Lyon will form the cross-border segment of the axis connecting western Europe to the east completing the Trans-European Rail network by developing passenger and goods transport.

The Lyon-Turin section, entails the construction of a 57 km long cross-border base tunnel crossing the alps, starting at St Jean de Maurienne (France) and exiting in the Valley of Susa (Italy), which will be one of the longest train tunnels in the world. The project has been the source of heavy criticism and intense mobilization, especially concentrated in the Val de Susa but also across Italy under the banner of the No-TAV (Treno Alta Velocità) movement.

NO TAV main objections to the project look at the pattern of infrastructural and environmental planning at local and national level and at the environmental, energy and economic costs of the project compared to its claimed benefits. In addition to the impacts on the environment and health, the movement has focused on the unnecessary construction of the expensive high-speed line and the presence of illegal economic activities and loss of public money through corruption.

One of the prime strengths of the movement is that apart from reacting and opposing to the implementation of a project, it has been able to channel its energy into pro-active and propositional activities. At the local level by opening new sites of struggle in the valley (protests against the Beltrame steel plant and the enlargement of the Frejus tunnel). At the national level with the promotion of alliances with other local movements within the Patto di mutuo soccorso, a methodology of struggle based on principles such as mutual aid, information sharing and active solidarity. The No Tav movement has therefore managed to extend a struggle over territorial issues into a broader and more complex critique of the model of development, at the same time leading to experiments in new forms of democratic participation and new practices that refer to degrowth theory.

The conflict started in the 1990s when the TAV Turin-Lyon was developed and the first national march against High Speed happened in 1995. The movement has grown and strengthened considerably over the years receiving national and international support. In 1996, the Institutional Committee was founded, putting into practice the theory of participative democracy for the exchange of information and for decision-making especially in crisis moments.

After 2000, TAV promoters proposed, changed and passed preliminary projects, the EU categorized the TAV Turin-Lyon as a priority infrastructure project and strong protests arose, in particular contesting the assessment of impacts and the externalities of a new line. The escalation of the conflict increased even more with the initiation of geological soundings without local consultation. In 2005, around 50 000 inhabitants of the valley occupied the excavation site and set up permanents pickets, paralyzing all work until the demonstration was brutally broken up by the police forces. Despite a financial scandal in 2005 within TAV S.p.A., the EU granted in 2008 €671 million in funding studies and works for the project for 2007-2013, recently extended to 2015 but halved for delays in the execution of works. In spring 2011 was held a political meeting of local and national leaders to re-launch the project and to set the re-commence of works for the geognostic tunnel in June. These events stimulated another strong cycle of mobilization, violent repression, and an intensified criminalization of the NOTAV demonstrations that has seen numerous clashes between police and protesters, and hundreds of arrests in the last years, up to the latest in December 2013.

The initial program intended to link Lisbon to Kiev but Portugal and Ukraine pulled out of the high speed line project.

The TAV Turin-Lyon, totalling 235km, is divided into 3 segments: The French one managed by Réseau Ferré de France (RFF) would go from Lyon to St Jean de Maurienne, will consist of a mixed line for freight (120 km/h) and passengers (220 km/h). The international section, with Lyon Turin Ferroviaire (LTF), an Italo-French company in charge, would connect St Jean de Maurienne, France, by a 57 km tunnel to Susa, Italy. The Italian section, under the control of the Italian railway network company Rete Ferroviaria Italiana (RFI) will connect Susa to Turin via a series of tunnels openly-dug or concealed with man-made hills.

The TAV project proposals have evolved and expanded for almost two decades.

Main project steps:

•In 2001 France and Italy ratified an international agreement for the construction of the Lyon-Turin railway connection;

•In 2006 the TAV Turin-Lyon Observatory was created to assess feasibility and evaluate alternative proposals. The last planning agreement it presented, recommended a slight reduction of land use for the construction of the line and changed the entrance and exit of the international tunnel, enlarging it by some kilometres to end up with a 57 km tunnel.

•In December 2008, the European Commission decided to reserve €671.8 million for studies and preliminary works on the Italian-French common section for the 2007-2013 period (later extended to 2015 for delays in the execution of works). The payment of these funds dependes on the capability of both beneficiaries to respect the project deadlines indicated in their submission for TEN-T co-financing.

•In 2011, the Italian Comitato Interministeriale per la Programmazione Economica (CIPE) approved the Preliminary Project, which had paved the way for work to start at La Maddalena and the future design works for the access routes on the Italian side. The actual project will be implemented in phases in order to reduce costs. This means that on the Italian side, in the first phase only the base tunnel, the Susa station and a short stretch (2 km) of the Orsiera tunnel will be built.

•In 2012 France and Italy reinforced their commitment to the project by signing, an amendment to the 2001 Treaty of Turin. This new agreement established the relative share of the costs between France and Italy (base tunnel: 42% paid by France and 56% by Italy and support by EU funding). Italy ratified the agreement in April 2014.

•In 2012 started the excavation works at the "La Maddalena" access tunnel site for the international section

•In March 2013 the EU Commision adopted a revised funding decision due to the dalays in the execution of works. The decision provides for a co-funding amounting for preliminary works to €395.2 million.

The project for the Italian section is still in its preliminary phase. The planning and cost of works of the national segments are still uncertain.

The Level of investment is provisional, uncertain and constantly growing. Costs of investment and maintenance are unclear. The estimate cost of the base tunnel of the international section is 8,5 billion€ divided between the two countries and the EU should finance the 40% of the amount. The preliminary project presented by Italy presented a cost of 4,4 billions € but datas are still uncertain. The france section is expected to cost between 11 and 14 billion€. The total cost prevision reached 25 billion €.