The fact that PSG won the champions League final this past season is not a guarantee that they will or they are going to win it again just like what happened to Manchester city after they won the champions League final the next season they were unable to play even semi finals.so the same may happen to PSG, I believe this your comment of comparing PSG and real Madrid is because of the poor performance of inter Milan at the champions league final.I think as long as champions League is concerned no team has won it more than real Madrid so comparing PSG that is just winning it for the first time with real Madrid is not it at all because the gap is really much. So the fact that they were able to defeat inter Milan doesn't mean that if they were to play with another team that would definitely defeat them in same manner.Is just that people were thinking that inter Milan is good and because of that they were over rated to be in good form which they were not.
It's a big achievement for PSG to win their first ever UEFA title and become the second french team to grab that title. There are cases where teams have won back to back titles and also there are scenarios where defending champion is eliminated in initial stages. It's because new season is a new beginning for every team and the one who overcome mistakes in previous season either wins the title or finishes at last stages of the season. For now PSG team and fans can celebrate the win while teams like Milan, Barcelona may sit back and review what actually went wrong in the last season.