Thiago Silva, Eric Maxim Choupo-Moting and Sergio Rico will all finish the season with PSG.
Although the Ligue 1 season was cancelled, with the Parisians declared as champions, Thomas Tuchel's side are into the Champions League quarter-finals.
A mini-tournament will be played in August to finish the competition, and Tuchel will have three free agents at his disposal.
"We have always played with these players and therefore we lose quality with their departures, that's for sure," Tuchel said.
"After that it will not be impossible and I am convinced that we will be very strong. We have to prepare this team for the two finals with a very good mentality.
"We played an extraordinary Champions League with everyone. It is different but not impossible."
Brazil veteran defender Silva has been one of interest to AC Milan, Arsenal and Everton.