Les Parisiens are mulling over whether to launch a further bid to overturn the Brazilian's suspension following an episode of misconduct in a Ligue 1 fixture last season
The sporting director was originally suspended for nine months by the French Football Federation (FFF) for shoving referee Alexandre Castro following les Parisiens' 1-1 draw with Valenciennes in May.
The Ligue 1 champions subsequently appealed that initial ruling, but their efforts have proved unsuccessful, and authorities chose to extend the ban by a further three months this week.
The decision means Leonardo is banned from carrying out his duties for the club until June 2014 - 13 months on from the incident - and PSG revealed they are now discussing what action to take next in an official statement on their website.
"PSG take note of the decision of the FFF's appeal committee, which was released on a statement on its website that pronounced against sporting director Leonardo and the potential points punishment against the club," stated the club.
"PSG regret the enhanced severity imposed by the committee against Leonardo, who continues to have our full confidence.
"Having received and considered the reasons for the decision of the High Commission of Appeal, the club will consider potential remedies."
The Brazilian joined the club in June 2011 and has played a key role in the club's high-profile recruitment policy.