Two second-half goals from Berbatov, an 88th-minute effort by Geoffrey Kondogbia and Lucas Ocampos's injury-time coup de grace led the visitors to victory while Junior Tallo replied for already-relegated Ajaccio.
Laurent Blanc's PSG can clinch the title with a win at third from bottom Sochaux on Sunday.
PSG, who won the French League Cup by beating Olympique Lyon 2-1 last Saturday, have 82 points with four games remaining. Monaco are seven points adrift with three matches to go.
- Sports & Recreation
- Geoffrey Kondogbia
- Lucas Ocampos
- Laurent Blanc
- Junior Tallo