For PSG being able to remain formidable this season is sure. They will be good or even better but what I cannot guarantee is PSG being able to win the champions league for the second time in a row.
Other clubs will rise up to the challenge and would likely out perform PSG, especially Liverpool FC.
No I don't think any other teams can be able to replicate what Real Madrid has done in recent times by winning the champions league back to back. PSG doesn't have it in them to win it th second time, their win this season was a lucky one because if they had met informed teams they won't had stand a chance. Next season favourite still has to be Real Madrid, you can never write them off in a champions league campaign. They might get some misfortune but be rest assured they aren't missing that many champions league finals and lifting the title. There's another underdog that many people will be neglecting but they do know how to win cup conceptions and that's Chelsea.