A small group of Barcelona fans have quietly begun a process that could bring about seismic change in European football after they went to court over the transfer of Lionel Messi to Paris Saint-Germain. Lawyers appeared on Tuesday before a senior judge at the European court of justice to argue that Messi’s move from Catalonia to Paris broke European laws on state aid and call for the European Commission to investigate the transfer. The session in Luxembourg lasted three hours in front of Judge Marc Jaeger, a former president of the court. The hearing was in effect an appeal, after an original claim against the European Commission was rejected. A verdict is expected within two months. Messi joined PSG in the summer of 2021 in perhaps the most high-profile transfer of modern times. The seven-times Ballon d’Or winner left on a free transfer and agreed a contract reported to be worth £94m over three years. Last month Uefa found PSG to have been in breach of its financial fair play regulations during this time and demanded €65m by way of financial settlement. The Barça supporters’ case argues that the French football authorities should never have allowed the Messi transfer to go through and that it distorted the competitive environment in continental football. But in calling for an investigation by the European Commission into the deal, they are also hoping to bring the world of football finance away from the game’s governing bodies and into the scope of Europe’s lawmakers for the first time. According to notes provided by the European Court, the full claim by the fan group would lead to the original decision by the court being overturned and the commission instructed to “order the French Football Federation to immediately cease any … distortion of competition and to bring itself into compliance with Uefa club licensing and financial fair play regulations”. It also calls on the commission to instigate proceedings against the French government, for “illegal state aid to PSG and the French football clubs in national and European competitions”. The case was heard against the backdrop of a dispute over the future of European football. Despite the collapse of the Super League last year, there is constant tension between clubs, competitions and their governing bodies. The three remaining “super league” clubs – Barcelona, Juventus and Real Madrid – have taken Uefa to court claiming the governing body acts as a monopoly. PSG have insisted the signing of Messi did not breach FFP regulations and on Tuesday a source said: “There is nothing to comment on – PSG isn’t even a party to the case.” The Ligue de Football Professionnel, which runs France’s major leagues and operates under the authority of the FFF, was approached for comment.