City - 3.25
Real - 3.95
Arsenal - 9.85
Liverpool - 11.10
Bayern - 12.70
Barcelona - 13.10
PSG - 16.80
It is surprising that Arsenal is higher than Bayern, Barcelona and even PSG. It is also not clear why City is considered the favorite, Real is the record holder in this tournament, although I probably agree with this, City really played better than Real. Probably in this rating I disagree only with the position of Bayern and would raise it higher.
According to this odds from this bookmakers, Arsenal is the third favorite teams after Madrid and Manchester City. They make the prediction based on assumption and consider Madrid and City first because of their their experience and their squad quality. Arsenal to be ranked ahead of Bayern Munich , PSG, and Liverpool can be because of their current squad especially their defensive quality, and their last two seasons performances in their domestic League which is the EPL.
Nevertheless, anything can happen because the teams we are expecting to be the champions might end up not performing well or unluckily get eliminated along the line especially if they are both paired together when the competition advances to either knockout stage of quarterfinals.