We were drawn to travel to Germany for the one-off tie in Friday’s event in Nyon.
The match is expected to be played on either Tuesday 27 February and Wednesday 28 February. The exact time and date of our game will be confirmed in due course.
Should it be a draw after 90 minutes, the winner will be decided on penalties.
Should we progress following that match, we will host either AZ Alkmaar or Porto in the quarter-finals.
At the semi-final stage, we would play the winners of the fourth quarter-final - one of Milan, Braga, Real Madrid or Leipzig.
City qualified for the last-16 by topping Group G with 14 points from our six matches.
Mainz reached this stage after eliminating Barcelona on penalties following a 2-2 draw. The German side originally qualified for that match through the domestic champions path.
Our best finish in the competition came in 2017/18 when we reached the semi-finals before losing to eventual winners Barcelona.
Round of 16 draw in full
AZ Alkmaar v Porto
AC Milan v Braga
Real Madrid v RB Leipzig
MSK Zilina v Copenhagen
Salzburg v Nantes
Olympiacos v Lens
Bayern Munich v Feyenoord
Mainz v Manchester City