Bartomeu told the Barcelona sports daily Mundo Deportivo: "He is the best player in the world and he is paid like the best in the world.
Barcelona announced Wednesday that Messi had agreed to extend his contract until 2021, in a deal that will keep the five times winner of the Ballon D'Or at the club until he is 34.
No financial terms were disclosed but Bartomeu told the Barcelona sports daily Mundo Deportivo: "He is the best player in the world and he is paid like the best in the world and in the history of football.
"He is the best paid sports player, because no one brings as much to his club as Leo Messi."
Prior to his contract extension, Messi was the third highest paid sportsman in the world with an income of $80, million of which 53 million was in salary and bonuses, according the ranking published by Forbes magazine in June.
His great rival, Real Madrid's Cristiano Ronaldo of Portugal, topped the ranking with $93 million, of which 58 million was in salary and bonuses, ahead of American basketball player LeBron James ($86,2 million of which 31,2 million in salary and bonuses).