Inter are still fighting for their league while PSG have been crowned winners already, they’ll be more prepared and rested for the UCL final to give their best on that day for the title that has so eluded them.
That's an advantage for PSG because they can focus more, especially since Napoli & Inter Milan are only 1 point apart in the Serie A standings after Napoli could only draw against Genoa. In addition, bookies also favor PSG with @2,24 odds, while Inter Milan with @3,25. This UCL final match will certainly be a very interesting match, we'll see what happens later, I hope PSG can win so they can make history for their club in getting the UCL trophy.
PSG has far more options now to control for muscular exhaustion. Just look what they did against Montpellier and at the same time Inter Milan has to be careful with players like Martinez. He has been out because of muscular fatigue for over a month in total now and they are trying to give the time he needs to be recovered as much as possible until that final takes place while not risking to give up on the Scudetto.
PSG has a few players who have been prone to muscular exhaustion in the past and the most important of them is Dembele and they will be giving him breaks. For both clubs the CL is probably highest priority, but Inter Milan has to try everything to win that Scudetto.