Winning and losing in this match will not change anything, there are only two matches left which means these two teams will still qualify. For example, maybe we assume PSG lost here and Club Brugge won and thus, their points are 8 and 7. Then, in the last match PSG will play at home against Club Brugge, we assume the result is a draw and their points will be 9 and 8, right. So, whatever result in the match Manchester City - PSG does not change anything in the standings of this group, their position will remain like that until the end. Even though PSG can win against Manchester City tomorrow, it's still these two teams that will qualify too, of course, unless Club Brugge can win in these last two matches then Club Brugge will certainly qualify. I'm not sure PSG will give up easily at home in the last match because the opponent is only Club Brugge, which it looks like PSG will still win in the last match against Club Brugge later.
It is 100% guaranteed in my mind that City and PSG will go to next stage, I do not believe that there is any possibility that Bruge would go to next stage. It is sad to see Leipzig doing that badly, that is the only thing that shocked me this year, they are not doing well in bundesliga as well, manager really does make a big difference.
In any case I assume that we will see City and PSG on next stage and then also another stage for sure, quarter finals is where things "may" get serious depending on your draw, but aside from that nothing really changes for these teams, hell maybe they could get some lucky draw on quarter finals as well who knows. They are not even working too hard right now neither, because they know they could get it done. Let's see how things could change, but at the moment it is going to be basically exactly this ranking by the end.