The striker netted a hat-trick against Nice at the Parc des Princes to reach the milestone and help the Ligue 1 champions to a 3-1 win on Saturday.
Ibrahimovic's treble marked his 13th, 14th and 15th goals of the season, which have added to his 35 strikes in all competitions from last term.
"It was a good night," Ibrahimovic told PSG TV. "We won and I scored three goals. I am very happy. I didn't know it was my 50th goals for Paris.
"For the moment, everything is going very well. It was a difficult match and it was very important to win.
"It's a good way to build the confidence before heading off with the national team. We are playing well and staying focused."
It took Ibrahimovic 63 games to achieve the accolade and put him in the top 10 of the club's all-time record goalscorers.