Maxwell's new deal will take him into a sixth season at the Parc des Princes, having enjoyed a trophy-laden spell in the French capital.
Since joining from Barcelona, Maxwell has won four Ligue 1 titles, two Coupe de France medals and tasted success in three Coupe de la Ligue campaigns, with PSG having secured a clean sweep of domestic honours in each of the last two campaigns.
Maxwell has made 181 appearances in that time.
"It's a great pleasure to extend my contract with Paris Saint-Germain," Maxwell said in a statement.
"I get along very well with the players and everyone at the club. The story goes on and I am extremely happy.
"I hope to take the team forward, think about the squad first. We will keep on being competitive, try to go as far as possible in every the competitions. We want to win as many titles as possible, the club deserves it."