The 32-year-old, formerly of Inter and Barcelona, has made 27 appearances for the Ligue 1 leaders this season.
He will now remain with PSG until the end of 2015 after the club opted to trigger an extension clause.
Maxwell is delighted to have extended his stay in the French capital and has vowed to help the club in their quest for domestic and European silverware.
"I am very proud of the president Nasser Al Khelaifi's confidence in me," he told the club's official website.
"I will continue to give my all for the club and our supporters to pay back this confidence. Dream bigger!"
Al-Khelaifi added: "Maxwell is an exceptional player who contributed greatly to the club since his arrival.
"I wished him to be a part of the project at Paris Saint-Germain over the long term."
Maxwell is the third player to sign a new deal at the Parc des Princes in recent weeks following midfielders Thiago Motta and Blaise Matuidi.
