The attacking midfielder has signed a contract with the Club until 2023 and will wear the number 27 shirt.
Lucas, 25, came through the ranks at Brazilian side Sao Paulo, where he went on to score 22 goals in 86 appearances as well as winning the Copa Sudamericana in 2012.
The Brazil international moved to PSG in January, 2013 and played 229 times for the Parisians, scoring 46 goals.
While at the Parc des Princes, Lucas won four Ligue 1 titles, three French Cups, four French League Cups and five French Super Cups.
He has represented his country on over 30 occasions to date and lifted the FIFA Confederations Cup in 2013.