This is particularly relevant in the current context, as pension funds, sovereign wealth funds, investment banks and other financial institutions are increasingly involved in financing transport infrastructure. A lack of transparency can be perceived negatively by the public and turn a simple transaction into a complex political process, distracted by particular interest groups. Since some concessions are established over long periods (50-75 years), they raise the problem of changing market conditions, which may require a renegotiation of the contract. It is almost impossible to anticipate long-term market changes and traffic, so a renegotiation clause in concession agreements should be considered. This renegotiation can also be the subject of controversy and public debate, especially when conducted in an opaque manner. While public opinion tends to associate PPPs with road tolls, reality places these initiatives in all segments of the transport sector, from modes of transport to terminals. . . .