PSG has now claimed the prestigious cup on 14 different times.
Paris Saint-Germain required a stoppage-time equaliser followed by a successful penalty shootout to overcome their arch-rivals in the Gulf and capture a fourth straight Trophee des Champions victory.
The European champions appeared to be sailing towards a comfortable win in the showdown between the Ligue 1 champions and the French Cup holders after Ousmane Dembele found the net in the opening stages.
However, Marseille fired two times late to seize a shock lead. Initially, the English forward converted from the penalty spot, before the defender unfortunately turned the ball into his own net for an own goal.
In a remarkable twist of events, the Portuguese striker grabbed a vital equaliser in the dying seconds to force the match into a penalty shootout. PSG goalkeeper Lucas Chevalier then stood as the key figure, stopping decisive attempts from O'Riley and Hamed Traore.
From the spot, Goncalo Ramos, Vitinha, the full-back, and Desire Doue all scored successfully for Paris Saint-Germain to seal a 4-1 penalty victory.
Now 14-time champions Paris Saint-Germain, who faced last season's Ligue 1 second-placed team Olympique de Marseille after achieving a league and cup double, have now won this trophy for the 12th time in the last thirteen years.
