Of course, both clubs will take the match very serious but the club that can outsmart the other will definitely win the game. I can't say which of these club is the strongest because City has been a mess to themselves recently, and they find it difficult to defend their goal after taking the lead. PSG is also not determined this season in UCL, because I don't see any motivation in them.
PSG and Manchester City must both improve their way of playing in the Champions League this season especially when they will meet in the next match in the Champions League this season. I also can't say about the prediction of who will win their match because both of them have not been so good in the Champions League this season so it's hard to say about the prediction of who will win between them.
Yes, both of them are not that good in the Champions League. Man City, who previously was a strong candidate in the UCL, also experienced a decline, but as @Frankolala said, PSG seems to have no determination in the UCL because they have only won 1 out of 6 matches, so if they lose against Man City, I think they will give up because they seem to have no hope in the UCL.