Premier League champions Manchester City have been fined £49m and had their squad for next season's Champions League capped at 21 men.
It is also reported that City will only be allowed to spend a total of £49m in this summer's transfer window, which they have agreed to, and that their wage bill must not be larger than this seasons as minimum signs they will make an active move to cut their budget in accordance with UEFA regulations.
This comes after it was reported that City severely broke the Financial Fair Play rules which were introduced in the 2011/12 season.
Paris Saint-Germain also breach the rules and have been given the same punishment as City.
A Manchester City statement read: "At the heart of discussions is a fundamental disagreement between the club's and Uefa's respective interpretations of the FFP regulations on players purchased before 2010.
"The club believes it has complied with the FFP regulations on this and all other matters.
"In normal circumstances, the club would wish to pursue its case and present its position through every avenue of recourse.
"However, our decision to do so must be balanced against the practical realities for our fans, for our partners and in the interests of the commercial operations of the club."
City's combined losses over the last two season came to a whopping £149m - £97m in 2012 and £51.6m in 2013.
FFP was originally introduced by UEFA in order to secure the long term futures of clubs, many of whom were spending themselves to administration.
Seven other clubs breached the rules as well, including Russian teams Zenit St Petersburg, Rubin Kazan and Anzhi Makhachkala, Turkish sides Galatasaray, Bursaspor and Trabzonspor and Bulgarian club Levski Sofia.
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