Paris Saint-Germain have been hit with a fine from UEFA that could rise to €65million after failing to comply with break-even rules put in place by European football's governing body.

The Ligue 1 champions were one of eight clubs served with financial fair play penalties, with Roma, Milan, Monaco, Besiktas, Inter, Juventus and Marseille the others affected.

UEFA said its Club Financial Control Body analysed the financial years 2018, 2019, 2020, 2021 and 2022 for clubs that competed in its European competitions last season, with special measures applied for 2020 and 2021 due to the pandemic's impact on football.

PSG have invested heavily in star players including the likes of Lionel Messi, Sergio Ramos and Gianluigi Donnarumma, while retaining the likes of Neymar and Kylian Mbappe in their ranks.

They must pay €10m, with the remainder of their punishment suspended for now, payable only if they fail to meet future targets.

Given the wealth of PSG's Qatari owners, questions will be asked about how significantly any such fine might affect the French giants.

Italian club Roma were served with a €35m fine, but similarly to the PSG case, only €5m of that is unconditional. They will avoid paying the rest if they meet UEFA requirements in future. Roma, managed by Jose Mourinho, won last season's Europa Conference League.

Their Serie A rivals Inter, Juventus and Milan were hit with €26m, €23m and €15m punishments, but must pay only €4m, €3.5m and €2m initially.

Turkish outfit Besiktas were fined €4m, but will pay €600,000 for now, while PSG's domestic opponents Marseille and Monaco were each penalised €2m, required to pay just €300,000 if they toe the line.

UEFA said: "These eight clubs agreed to financial contributions of €172m.

"These amounts will be withheld from any revenues these clubs earn from participating in UEFA club competitions or paid directly.

"Of this amount, €26m (15 per cent) shall be paid in full while the remaining balance of €146m (85 per cent) is conditional depending on these clubs' compliance with the targets stated in the respective settlement agreement."

Those settlement agreements will span three or four years. Inter and Roma requested four-year terms, while all other clubs elected for three years.

UEFA said the clubs would "undertake to reach intermediate annual targets, and to the application of conditional financial and sporting measures should these targets not be met".

It added that 19 further clubs, including Borussia Dortmund, Chelsea, Barcelona, Manchester City, Sevilla, Lazio, Napoli and West Ham, fulfilled the break-even requirement only "thanks to the application of the COVID-19 emergency measures and/or because they benefited from historical positive break-even results".

UEFA said these clubs would be "further asked for additional financial information and will be monitored closely in the upcoming period".