Some of City's sponsorship deals came under renewed scrutiny in Wednesday's instalment from Der Spiegel, which claimed that City remain sensitive to allegations of human rights abuse in the United Arab Emirates.
FFP was announced by UEFA in 2010, set to come into force for the 2013/14 season, with clubs threatened with sanctions, including potential Champions League expulsion if they failed to comply.
In the latest allegations to plunge City into turmoil, it is alleged a risk analysis regarding a possible deal with Arabtec was carried out by executives but that, despite the report concluding a partnership with the company would have "significant potential to damage the perception and standing of the club and its owners", the club struck an agreement regardless, signing a regional contract that would be publicised only in Arab states, Russian Federation and Turkey, where there was considered to be less risk of condemnation.
Gianni Infantino, the Federation Internationale de Football Association president, was alleged at the weekend to have struck a secret deal with the club when he was at Uefa which meant they avoided a Champions League ban.
Joris Evers, chief communications officer for Spain's top flight La Liga, told BBC Sport: "The Football Leaks documents [in der Spiegel] appear to confirm what we have been saying for years".
La Liga, the Spanish top flight, has said that, if UEFA does not act, it will "launch a complaint with European Union competition authorities". And we want to do what we have to do in terms of the rules.
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That included selling players' image rights to an external company, therefore writing off that cost from their accounts.
The official response from City to Der Spiegel's request for comment remains, "The attempt to damage the Club's reputation is organised and clear". This was followed up by further claims on Monday and Tuesday, including suggestions sponsorship deals with Abu Dhabi-based companies were topped up by discrete payments from City's owner Sheikh Mansour. At the time of the email, France legend Michel Platini was Uefa president.
"We will need to fight this", Soriano wrote, according to the magazine, "and do it in a way that is not visible, or we will be pointed out as the global enemies of football".
Der Spiegel calls the settlements "weak" and claims Uefa "wasn't even entirely aware of the degree to which it had been deceived". When auditors PricewaterhouseCoopers later reviewed the Fordham deal on behalf of UEFA, it was concluded that it was a "very good deal for MCFC", not least because the auditors couldn't figure out how Fordham expected to make any money on the deal for themselves.
Since 2008, City have won three Premier Leagues, an FA Cup and three League Cups, and have spent more than £1.4bn on players.