Chelsea vs PSG final is like the popular opinion but like you rightly said, it is not a good idea to assume that Real Madrid is a push over for PSG because Real Madrid is a good team and have demonstrated that in the few recent matches. If at the end of the day Madrid wins PSG, it will not come to me as so much shock because Madrid is capable of achieving that against PSG the European champion. Both teams have quality players, almost same grade of players so it will be a very big match to watch that day.
What is the guarantee that Chelsea will even beat Fluminense FC? The Brazilian side has proved to be a strong side that shouldn't be underrated. They were able to beat Inter Milan by two goals, so Chelsea should be ready for a fight.
I will not conclude that PSG will defeat Real Madrid. Maybe because of their recent exploit in the UEFA Champions League. Los Blancos have what it takes to surprise the current European champions.