Before the start of his performance, the player burst into tears, and the journalists supported him with applause.
Messi is a graduate of Barcelona, in which he played since 2003.
Together with the Catalan club, the striker has won 36 trophies.
The Argentinean has 672 goals and 305 assists in 778 matches.
On July 1, he became a free agent, and on August 5, the Blue Garnet announced that he would not remain with the team.
Earlier, the president of Barcelona announced the transfer of Messi to PSG.