i think inter will win mainly because of PSG 's weak defense and inter being good overall.
There's a lot of advantages they both have; one way or the other, they have something that would convince me that they both won't misuse an opportunity if it shows up cheaply, like it did to Tottenham against man United. Being too prepared for something can build serious over-confidence -- may have been delevoped for good, but the after effects would be simple mistakes and reluctance.
Inter winning the UEFA Champions League would make Serie A much stronger, and bring more exposure towards the league. PSG will also break a long-standing spell of not having at least one of the Champions League trophy.
This will not be easy, seen from any side Inter Milan and PSG have almost the same both in terms of team quality and motivation for the final match later.
Maybe Inter Milan is only superior in terms of mentality because they are filled with many senior players and have also won the Champion League title while PSG has not and for the rest I think there is none so the final match later is difficult to predict because in terms of percentage it is quite the same between Inter Milan and PSG.