The Brazilian was initially handed a nine-month ban for pushing a referee following a Ligue 1 clash with Valenciennes on May 5, but, after a failed appeal, it was increased on Thursday to expire on June 30, 2014.
It means Leonardo cannot be present on the touchline or enter referees' dressing rooms for the entirety of next season.
A statement for the defending Ligue 1 champions read: "Paris St Germain acknowledges the verdict passed down by the French Football Federation's Appeals Commission, published on the Federation website on Thursday, concerning the Club's Sports Director Leonardo and the conditional withdrawal of points for the club.
"The club deplores the severity of the new, harsher penalty handed down by the Commission to Leonardo, in whom the club reiterates its total confidence.
"Paris St Germain will consider its future legal options once it has received and studied the wording of the Appeals Commission's decision."
Leonardo is alleged to have barged into referee Alexandre Castro in the tunnel after the Valenciennes match and has been provisionally suspended since.
The 43-year-old had claimed he was pushed into the referee by the principal match delegate Marc-Gerard Biolchini, but the disciplinary committee that initially ruled on the matter decided his action was deliberate.
Leonardo was outspoken in his criticism of referees last season and described the sending-off of defender Thiago Silva in the Valenciennes match as "unacceptable".
PSG were also handed a suspended three-point deduction for next season, but the FFF elected to pass on the club's appeal against that sanction to the Ligue de Football Professionnel (LFP), who first handed it down.