Akanji made 40 appearances for City last season. Fabrizio Romano reports that Galatasaray reached an agreement with the Citizens some time ago for a transfer valued at the same £15 million fee.
However, the player himself has not yet given his consent. Bayer Leverkusen have also shown interest in the defender.
Akanji wanted by Crystal Palace
According to The Sun, via Sportal, Crystal Palace have made a move for Akanji, offering £15 million, which includes performance-related bonuses.
The 30-year-old Swiss international is being targeted as a replacement for Marc Guehi, who is widely expected to join Liverpool before the transfer window closes.
Yesterday, a rumour emerged that Manchester City could make a last-minute move for Guehi themselves, should they manage to sell both Akanji and Aké.
Pep Guardiola left the Swiss defender out of Manchester City's squad for their weekend match against Tottenham.