The current odds for the CL winner:

Liverpool are top favourites which isn't a big surprise.

I didn't expect PSG to go to the top in only one year according to bookies. But they are once again a serious favourite with this game surely.
Real Madrid come as the 2nd... Maybe this can be criticized as they have a brand new manager now. But I hope Xabi Alonso won't show a bad performance in his first year.
PSG come as the 3rd which is also okay. Some websites are even showing PSG - Arsenal in equal odds.

They have done well with their recent recruitment. They need to get a new striker if they finally let go of Darwin Nunez whonis wanted by Napoli. They looked more like favorites for the Champions league last season than this season. I'm certain they'll be back stronger and better
I don't expect much from Real Madrid. Not in the Champions League, not even in the La Liga Competition. I say Barcelona wins it again.

PSG are moving ambitions, they have what it takes win it back to back. The president already said it, they'll try to win the competition again.