Uefa on Friday authorised AC Milan, Aston Villa and Brighton to take part in European competitions next season after they made changes to avoid potential conflict with the multi-club ownership rule.
Seven-time European champions Milan share the same US owners, RedBird Capital Partners, as French Cup winners Toulouse, while Villa's owners have a stake in Portuguese club Vitoria Guimaraes.
Brighton owner Tony Bloom became the majority shareholder of Union Saint-Gilloise when he bought the Belgian side in 2018.
European football's governing body had appointed investigators to study the links between the teams in question, but said it was now satisfied "no one has control or decisive influence over more than one club" participating in its competitions.
"Following the implementation of significant changes by the clubs and their related investors, the CFCB First Chamber accepted the admission of the aforementioned clubs to the Uefa club competitions for the 2023/24 season," Uefa said in a statement.
"The CFCB found that the significant changes implemented brought the clubs into compliance with the multi-club ownership rule.
It added: "These changes substantially restrict the investors' influence and decision-making power over more than one club, ensuring compliance with the multi-club ownership rule."
Uefa has multi-club ownership regulations in place to protect the integrity of its competitions when such teams could be drawn to play each other.
Rules do not allow a club to hold or deal in securities or shares of another club playing in a European competition and no club can be a member of any other club participating in Uefa competitions.
Additionally, no person has the power to be "simultaneously involved" in the management, administration or sporting performance of more than one club.
As part of complying with the rules, none of the affected clubs will be able to transfer players to each other, whether permanently or on loan, until September 2024.
Milan are due to play in the Champions League, with Brighton, Union and Toulouse in the Europa League. Villa and Vitoria are both in the qualifying rounds of the Conference League.