On Wednesday morning, French daily L'Equipe said that PSG were planning to bid for the pair. Then later on Wednesday evening, Italian sports channel Sky Sport 24 reported that the bid – believed to be €65 million (£51.3m) - had been accepted.
Ibrahimovic's agent Mino Raiola is thought to have had a four-hour meeting with Milan vice president Adriano Galliani about the potential transfer.
Raiola is now said to have flown to Sweden to talk over the deal with Ibrahimovic.
Swedish international Ibrahimovic, now 30, has a contract with Milan until the summer of 2015, while 27-year-old Brazil international defender Thiago Silva only extended his contract until 2017 this summer.
Milan are undergoing a rebuilding project this summer, having finished second to Juventus in Serie A last season.
They have already signed Riccardo Montolivo from Fiorentina and Bakaye Traore from Nice, with veterans Alessandro Nesta, Mark van Bommel, Gianluca Zambrotta, Filippo Inzaghi, Clarence Seedorf and Gennaro Gattuso all exiting the San Siro.
PSG, were bought by ambitious Qatari investors last May and have already shelled out tens of millions of euros on new signings.