Lavezzi joined the French outfit from Napoli earlier this summer, and Pastore has admitted that he cannot wait to play with his "friend" in the new campaign.
"I'm very happy with his arrival because he is a friend of mine. I got to know him in the national team, and his coming here has made me very happy," he told the club's official website.
"It's certain that he will bring us a lot going forward, and that is decisive for us. We know that he has great potential and that he will be an added asset to us."
PSG finished second in Ligue 1 last season.