English Premier League giants Manchester City showed "blatant disregard" in cooperating with UEFA'S investigation into Financial Fair Play breaches, the Court of Arbitration for Sport (CAS) has said.
The CAS panel that heard City's appeal published their full reasoning for overturning the club's two-year ban from European football earlier this month.
The decision allows City to compete in next season's Champions League.
Sport's highest court also reduced the fine for City's failure to cooperate with UEFA to 10 million euros ($A16 million) from 30 million euros ($A49 million).
European soccer's governing body UEFA ruled in February that City had committed serious FFP breaches and failed to cooperate with its investigation.
But City's "blatant disregard" for cooperating with the investigation should be "strongly condemned," CAS found, expressing hope the large fine would be a "sufficiently strong deterrent" to other clubs.
UEFA opened the probe in March 2019 after allegations that the City's Abu Dhabi owners inflated sponsorship agreements to comply with the FFP requirements. The leaked documents included club emails which referred to money being "routed" through sponsors.
CAS ruled that the leaked documents could be used as evidence but noted that they did not prove the existence of any actual transactions that broke UEFA's rules and no evidence was produced that such payments were carried out.
City did not supply UEFA's investigation with the original emails related to the leaked documents but CAS also noted that UEFA did not "pursue" that evidence before the hearing.
"UEFA's approach in this regard is understood, because it was faced with a dilemma between trying to obtain additional evidence and having an award issued before the start of the 2020/2021 UEFA club competitions season," said the CAS panel.