The current odds for Real Madrid - Manchester City game are:

Manchester City are favoured even at Santiago Bernabeu by a slight margin indeed. After recent performances by Real Madrid in the tournament I understand bookmakers about not showing Real Madrid as the favourite here. I wouldn't place a bet on a side for this game but in the rematch it would make more sense.

It is difficult to see how the odds are currently offered because seeing from the conditions, these two clubs cannot be predicted about who will win later.
Manchester City are slightly ahead in terms of odds compared to Madrid even though they play as an away club, I think it is also not a strange thing because after all, when looking at statistics, especially for the second leg which was quite dark last season and with their current condition which is nicknamed as defending champions, it provides special conditions about Manchester City which must be a favorite.
But surely this season Madrid is a little different than last season so we need to pay attention to that. Their midfield is still quite formidable now and it could be offset even though it is certain that in this first leg match Manchester City will definitely excel in possession but Madrid with its counter-attack specialists cannot be underestimated so maybe in this case I will do a slightly risky scenario where I will be in Madrid for the first leg.