Maxwell, who becomes PSG's first signing of the January transfer window, has agreed a three-and-a-half year deal with the club.
"From my first conversation with (director of football) Leonardo, I felt really wanted," Maxwell said. "The invitation to join Paris made me very happy. This suits from the path that I have taken before (playing for Ajax, Inter Milan, and Barcelona).
"The project and the prospects motivated me."
Leonardo added: "I have always admired Maxwell. I have followed him throughout his career. I'm really happy to have signed him."