The Ligue 1 leaders have triggered a one-year extension clause in the 32-year-old Brazil international's current deal.
The former Ajax and Inter Milan left back, who joined PSG from Barcelona in January 2012, admitted he was delighted with the news and said he would continue to put in the hard work as the Parisians try to defend the title.
He told his club's official website, psg.fr: "I am very proud of the president Nasser Al Khelaifi's confidence in me.
"I will continue to give my all for the club and our supporters to pay back this confidence. Dream bigger!"
Maxwell has made 91 appearances for PSG ahead of Sunday's league match at home to Marseille - scoring five goals - and he has won seven caps for his country since making his debut in August last year.
And president Al Khelaifi was pleased to tie the Brazilian down for another year, adding: "Maxwell is an exceptional player who has contributed greatly to the club since his arrival.
"I wished him to be a part of the project at Paris St Germain over the long term."
The news comes two days after midfielder Blaise Matuidi signed a four-year contract extension with the club.
The 26-year-old joined from St Etienne in 2011 and his deal was due to expire this summer, but it was widely anticipated that talks would result in him agreeing to stay on with the fast-progressing capital club.