Neymar was unable to lead a comeback on Tuesday as Mbappe watched from the sidelines – PSG beaten 2-0 by Manchester City, who progressed to the Champions League final 4-1 on aggregate.
Last season's runners-up PSG failed to land a single shot on target against City – the first time the French side have failed to do so in a Champions League game since 2003-04.
Attention immediately turned to the futures of star duo Neymar and Mbappe, who are both out of contract in 2022 amid ongoing speculation.
Neymar has previously said "everything is almost settled" in regard to a PSG contract renewal though he continues to be linked with a Barcelona return, while Mbappe has been tipped to join Real Madrid.
"Honestly, now is not the time to decide or announce anything," Leonardo told RMC Sport. "We must be proud of what we have done.