Paris St-Germain are still on track to achieve their third successive domestic title as victory over Monaco took them through to the French cup final.
After Monaco keeper Morgan de Sanctis spilled an easy save, Julian Draxler tapped the opener into the net.
Edinson Cavani with a second from Angel Di Maria’s cross, then Blaise Matuidi added to an own goal by Monaco’s Safwan Mbae.
Marquinhos rounded off the scoring with a late rebound after a deflection.
PSG will now go on to play Angers in the final at the Stade de France on 27 May.
Angers, 14th in Ligue 1, reached their first French cup final in 60 years with a 2-0 victory over Guingamp on Tuesday.
PSG trail Monaco on goal difference at the top of the French league, but Leonardo Jardim’s side, who host Juventus in the Champions League on Wednesday, have a game in hand.
PSG, who won the domestic treble twice in a row under previous boss Laurent Blanc, beat Monaco to win the French League Cup final 4-1 earlier in April.
Paris Saint Germain
Draxler (26′ minutes)
Cavani (31′ minutes)
Mbae (50′ minutes og)
Matuidi (52′ minutes)
Marquinhos (90′ minutes)