Liverpool is playing an easy match, PSG isn't in a good form to be a perfect match for them. Liverpool will definitely win PSG, and advance to the quarter finals because they have been the best club so far in the group stage. PSG wouldn't be a hinderance to them, since PSG is not that too good in UCL matches. I give Liverpool the victory both at home and away.
I think you too underestimate PSG. Don't you see PSG performed better recently? Considering their great performance against Brest, I am not sure Liverpool will easily defeat PSG. I even think PSG can eliminate Liverpool if PSG can win in Leg 1. You must be aware that Leg 1 will be in PSG home. It will be an advantage for PSG because they will have a chance to get a good start. Meanwhile for Liverpool, it will be a challenge because they will play away. Sometimes, the atmosphere of the stadium can bring big impact on the performance of the teams.