The World Cup winner had scans on his ankle injury on Monday that revealed he will miss the next three weeks.
"The results of today's scan confirmed an ankle sprain with damage to the external ligament," a club statement revealed. "The player is expected to be sidelined for approximately three weeks."
Mbappe will not be available for Friday's last ever Coupe de la Ligue final against Lyon and is also not due to return in time to face Atalanta.
The last-eight Champions League meeting in Lisbon will be played on August 12, although the forward could yet be fit for the semi-finals if PSG advance.