The Germany completed is switch to Eastlands over the weekend.
"I am really looking forward to the World Cup and then to joining City," he told mcfc.co.uk.
"I spoke at length with Roberto Mancini and he impressed me with his plans for the team in the coming seasons. It was a very good conversation.
"And I know about City from when Hamburg played here in the Uefa Cup. I played in the second leg which we lost but won on aggregate on the way to the semi-finals.
"I can't wait to work with so many top players and show what I can do and become a better player. I believe my strengths are my pace and reading of the game. I can play at full back on either side but I prefer the central defensive position."