City continue to be linked with a swoop for the Senegal international, but negotiations are understood to have reached an impasse between the two clubs.
As a result, City are reportedly eyeing up other defensive options - with Sevilla centre-back Jules Kounde rumoured to have agreed personal terms with the Citizens - and Koulibaly could therefore be heading to the French capital instead.
According to The Telegraph, PSG are also keen to bolster their defence following the departure of Thiago Silva, and the Ligue 1 champions are now at the head of the queue for Koulibaly.
The report claims that Thomas Tuchel's side are willing to fork out a sizeable figure of £75m for the 29-year-old, whom Napoli head coach Gennaro Gattuso has admitted could be on his way out if a suitable offer is received.
Koulibaly, who is contracted to Gli Azzurri until 2023, played the full 90 minutes as Napoli returned to Serie A action with a 2-0 win at Parma on Sunday. body check tags ::