(CNN) – UEFA initiated disciplinary proceedings against Real Madrid, FC Barcelona and Juventus for their participation in the European Super League.The three European giants were part of a group of 12 teams that announced their plans to form an independent competition in April.

After the new project received strong criticism, the other nine clubs (Arsenal, Chelsea, Liverpool, Manchester City, Manchester United, Tottenham Hotspur, AC Milan, Inter Milan and Atlético de Madrid) quickly changed their minds, expressing regret for their actions and re-engaging with UEFA club and national team competitions.

Meanwhile, Real Madrid, FC Barcelona and Juventus issued a joint statement earlier this month announcing that, despite “the unacceptable and continuous pressure and threats received from UEFA”, they intended to to persevere in the search for a solution to what they call an “unsustainable situation in the football industry.”

The governing body of European football issued a statement on Tuesday announcing the opening of proceedings against the three teams “for a possible violation of UEFA’s legal framework.”

The nine clubs that backed down were subsequently ordered to collectively donate € 15 million (US $ 18.2 million) to charities and give up 5% of the income they would have received from the competitions.

UEFA says the clubs have agreed to be fined up to 100 million euros (US $ 121.7 million) should they breach their commitments again. At the moment, it is not clear what kind of punishment can expect Real Madrid, FC Barcelona and Juventus after the UEFA disciplinary procedure.