"An agreement has been reached and he [Ibrahimovic] will be having his medical tomorrow [Wednesday]," Leonardo told reporters outside the Parc des Princes.
"It's a great year for PSG. That such a player is coming here is enormous, it can change everything."
PSG announced on the club's official website that they would be holding a news conference at 13:00 GMT on Wednesday when the striker is expected to be presented.
"It's a deal. I can confirm that," Ibrahimovic's agent Mino Raiola told Swedish news agency TT earlier on Tuesday.
Milan owner Silvio Berlusconi announced last week that he had sold Ibrahimovic, top scorer in Serie A last season, and defender Thiago Silva to the big-spending French club who were taken over by Qatari investors last year.
Ibrahimovic, 30, will join Argentine forward Ezequiel Lavezzi, who signed for PSG earlier this month, as the club from the French capital seek to play a major role in Europe.
They finished second in Ligue 1 last term and will now play in the Champions League.
Last season, they signed Argentine playmaker Javier Pastore as well as defender Alex and midfielder Thiago Motta.
Attempts to sign David Beckham and Carlos Tevez failed, however, despite the presence of new coach Carlo Ancelotti.
