Yeah, definitely its a football game it's wasn't easy to predict, but to be honest PSG didn't make any sense. This season PSG didn't play so well, especially in UEFA champions league competition. They played just awfully all of their matches are so poor. They lost against Arsenal, they drew against PSV as well they lost against Atlético Madrid and now it's a Bayern Munich turn. Considering this, I am pretty sure that PSG will lose this match. They are not doing anything good for UEFA champions league competition. Thus far, if we look at the status of PSG it is also not looking good. PSG winning ratios are far poorer than Bayern Munich. Besides Bayern Munich squad depth is also good as compared to PSG. So looking at these specs, I'm pretty sure that Bayern Munich will be the victorious.
Even with the presence of Kylian Mbappe, PSG were not considered as special in the UEFA Champions League competition. Killian Mbappe had well known goal scoring ability, but PSG did not win the UEFA Champions League title under his tutelage. It doesn't matter if Killian Mbappe is there or not, PSG is still a lay club.
You are right PSG has struggled in UEFA Champions League lately. They have lost to Arsenal and Atlético Madrid, and tied with PSV. Bayern Munich has stronger team and better winning record giving them an advantage. However PSG still has Kylian Mbappe who can change game. Although Mbappe has not led PSG to Champions League victory he remains threat. This matchup is exciting. Bayern Munich consistency might be too much for PSG but Mbappe could pull off an upset.