[en] A decade after the adoption of the third legislative package, this new edition of the CRE report on interconnections, covering the years 2018 and 2019, marks the coming of age of the internal market, but also the opening towards a new era, that of the decarbonization of energy in Europe. The European Union's stated ambitions represent a remarkable change of direction and bring with them many challenges. However, one certainty remains: the interconnections between national energy systems are an essential asset for the transition to more renewable energies and the reduction of greenhouse gas emissions at European level. The commitment to integration with neighbouring countries has been carried by CRE since its creation twenty years ago. This report once again demonstrates the very good level of interconnection achieved by France, both for gas and electricity. The decisions taken by CRE have been guided by the idea of solidarity between member states, in the framework of a balanced relationship and in the search for efficiency. The creation of a single gas market area in France reflects this ambition, which has made France a new strong point in the European market, with greater liquidity and lower network usage tariffs for international shippers. Developments over the last two years confirm the major role of interconnections in the construction of Europe. Electricity trade with the rest of the EU has increased sharply after the lows of 2016 and 2017. New interconnection capacity is being built with Italy, Spain and Great Britain, and 2019 marked the validation of the Celtic project, which will give Ireland direct access to the continental European market. Gas movements have reached historically high levels, both incoming and outgoing, reflecting the increased role of the French market in international trade. French wholesale prices have for several years experienced excellent convergence with European reference prices and are often even lower than the Dutch market reference in 2019. As regards the rules for the functioning of the internal market, 2019 marked the entry into force of the 'Clean energy for all Europeans' legislative package. After intensive efforts to implement the provisions of the third package in practice, some of the guidelines of the new rules raise questions. The level of detail achieved in the technical prescriptions is particularly high and raises concerns about a lack of flexibility or even a mismatch with the concrete realities of the electricity system. The provisions requiring to dedicate 70% of physical interconnection capacity to exchanges between member states therefore does not take account of capacity calculation rules and network operating constraints. This could be particularly costly if remedies were to be systematically applied. These measures, which are essentially based on re-dispatching and counter-trading can lead to extremely high levels of compensation for market players. If misapplied, these provisions could even lead countries that have invested most in the robustness of their networks to unjustifiably contribute to the remediation costs incurred by their neighbours with more fragile networks. This is a major concern for CRE as the French network appears particularly robust in the face of the development of cross-border trade, due to the investments made in its internal networks and financed by the French end consumer. The call for a fair balance between prescription and pragmatism in the European legislation is a message that CRE regularly conveys. At a time when reflections are advancing on the revision of the regulation on trans-European energy networks and when the texts implementing the Green Deal are being prepared, CRE calls for effective coordination between the national and European levels. Stimulating innovation requires promoting flexibility and agility, including at institutional level. In this respect, national regulators must be considered as assets, capable of setting in music a decentralisation that respects the coherence of the EU.