Real, brimming with confidence after their statement Champions League win at Manchester City midweek, sit comfortably on top of LaLiga on 78 points, ahead of Barca on 70 and Girona on 65
Uruguay forward Cavani was substituted after 13 minutes and scans confirmed a hip injury, while Mbappe, who limped off midway through the second half, has damaged his hamstring, PSG said in a statement.
Forward Neymar has not played this season amid uncertainty over the Brazil international's future.
Cavani and Mbappe will miss PSG's league games against Metz, Strasbourg and Olympique Lyonnais but could return before they face Reims on Sept 25.