Manchester City sought damages from Uefa for what they alleged were "unlawful" leaks to the media with regards to an inquiry into possible Financial Fair Play (FFP) breaches.
Senior Uefa official Yves Leterme had dismissed the club's claims, stating they were "groundless" and "unacceptable in tone".
Details of City's appeal against the FFP probe have been published by the Court of Arbitration for Sport (Cas).
An FFP verdict from Uefa's adjudicatory chamber is understood to be close.
In November last year Cas announced City's appeal to halt Uefa's FFP investigation was "inadmissible" because Uefa's Club Financial Control Body (CFCB) had not yet determined what, if any, punishment the club should face if found guilty of breaching spending controls.
The full appeal judgement shows that City argued that a decision by the CFCB investigatory chamber to refer the case to its adjudicatory chamber had been taken "improperly and prematurely".
They also argued Uefa had "systematically breached, and continues to breach, its express obligations of confidentiality", claiming individuals working within the governing body were briefing journalists. City claimed the investigation should be suspended and that Uefa should conduct an inquiry into the alleged leaks.
"These ongoing and egregious breaches undermine the very integrity of Uefa's adjudicatory process, which is a consensual dispute resolution mechanism with confidentiality at its core," City said in their written appeal submission.
In dismissing City's claim, Cas did say the appeal was "not without merit" and the alleged leaking of information by members of the investigation or the Uefa administration about the proceedings against City was "worrisome".
Leterme, who is the head of the CFCB's investigatory chamber, responded to City's claims of leaks in an letter sent in May last year.
In it, he wrote: "I must vehemently reject your allegations of unlawful activities, either by myself or by any of the members of the Uefa CFCB.
"Your allegations are groundless in the merits and unacceptable in tone.
"Please be advised that I will not continue such an exchange of correspondence and that I will not respond further to groundless accusations directed against me personally and/or against my fellow members."
Uefa launched an investigation after German newspaper Der Spiegel published leaked documents alleging City had inflated the value of a sponsorship deal, misleading European football's governing body.
Reports alleged City - who deny wrongdoing - deliberately misled Uefa so they could meet FFP rules requiring clubs to break even.
The Premier League, FA Cup and League Cup holders were fined in 2014 for a previous breach of regulations.
Uefa investigators previously said they want City to be banned from the Champions League for a season if they are found guilty of breaking financial rules.
No announcement on the outcome of City's case has yet been made by the CFCB's adjudicatory chamber.