"We have been probed by PSG about Lucas," Lopes told French newspaper Le 10 Sport.
"Leonardo has a very good relationship with Sao Paulo. But for now nothing is definite."
Lopes added the final decision was with the player.
"The possibility exists but it is down to the player's interests. The policy of Sao Paulo is to follow the desires of the player. If the player wishes to leave, Sao Paulo will not create any obstacle. But we must receive a proposal that is appropriate," he said.
"It's a financial issue. Paris St Germain is a big club in European football and if the player's interests and also the club's are met, I do not see why it would not happen."