UEFA has banned English football giants Manchester City from the lucrative Champions League competition for two seasons and ordered it to pay a fine of €30 million
It said the club had committed serious breaches of the European football governing body's financial fair play regulations.
UEFA said the Premier League champions had "overstated its sponsorship revenue" between 2012 and 2016.
The regulations were designed to stop super-rich clubs from ruining the sport by spending excessive sums on players.
Ex-UEFA president Michel Platini called the practice of outlandish expenditure "financial doping".
The rules require clubs to balance their football incomings, such as television income and commercial revenues, with their outgoings, which include transfer fees for new players and wages.
Manchester City said in a statement it would appeal the judgment.
"Manchester City is disappointed but not surprised by today’s announcement by the UEFA Adjudicatory Chamber.
"Simply put, this is a case initiated by UEFA, prosecuted by UEFA and judged by UEFA. With this prejudicial process now over, the Club will pursue an impartial judgment as quickly as possible and will, therefore, in the first instance, commence proceedings with the Court of Arbitration for Sport at the earliest opportunity."
The club appointed decorated Spanish manager Pep Guardiola in 2016 and, while he has delivered Premier League titles, he has yet to add the sought-after Champions League trophy to the Manchester team's cabinet.
The ban will take effect from next season, beginning in August.
Manchester City are through to the last 16 of this year's Champions League and will face Real Madrid in a first-leg match on 26 February.