Manchester city after getting the treble winner this year will definitely get so many bonuses that they have started to move to get new players in the summer. Gvardiol was one of the stars in last year's world cup and his performance with Leipzig is still fairly stable.
If I recall it properly then I think Romano had a tweet around World Cup about Gvardiol and City being interested in him before the WC. It's not a surprise and City seems desperate to get him from Leipzig. Personal terms seems to be agreed already but Leipzig expect a good amount of bid and I think they are expecting somewhat around 100m Euro at least for the defender.
Also City have opened talks with Chelsea over fee for Kovacic with personal terms already agreed. It really does seem that they are moving in transfer window now.