The Ivorian moved to the Etihad in January 2015, and a leaked copy of that transfer agreement has now been seen by Mirror Football.
In total, Bony could cost City as much as £33m, and that's before the sell-on clause.
City paid £9m up front, plus the £5m in VAT due on the total transfer. They paid Swansea a further £8m in January 2016 and are due to pay the Welsh side a further £8m in January 2017.
In addition to the 'fixed' cost, the documents posted online by Football Leaks reveal the breakdown of add-ons City may have to pay.
These add-ons are related to success in competitions in which Bony played at least 45 minutes in 60 per cent of their games.
Up to and including the 2018/19 season, City will have to pay Swansea £1m each time they win the Champions League, £600,000 each time they win the Premier League, £300,000 each time they win the FA Cup and £300,000 each time they reach the semi-finals of the Champions League.
There is a £3m limit on these add-ons.
Finally, if City were to sell Bony for more than £28m before the end of the 2018/19 season, Swansea would be due 20 per cent of the fee over that amount.
Bony, 27, has scored just 10 goals since joining over a year ago.
