According to the sources, the French team's director of football, Luís Campos, is traveling to Brazil to monitor the player in situ.
There is still no formal offer from PSG for Moscardo, however sources note that the French team's interest is serious -- with Campos' trip to Brazil demonstrating PSG's intention to ramp up their advances as the director only travels when negotiations for a player are serious.
People involved in the talks point out that the Ligue 1 leaders are the most interested club in Moscardo at the moment, and are in need of midfield options.
Corinthians are waiting to receive an offer of around €30 million ($32.9m) before proceeding with sale talks.
Before Moscardo turned professional, Barcelona also showed interest in the player but talks did not go ahead.
Promoted to the professional first team this season, Moscardo has made 23 appearances for Corinthians so far without registering any goals or assists.
He may start against Vasco de Gama on Tuesday in an important match in Brazil's top tier.