The 20-year-old Brazilian, born in Taubate, has signed with Espanyol until June 2027 despite the loan itself running for a single campaign, with the move giving Manolo Gonzalez another option in central midfield.
Moscardo came through the Corinthians academy before PSG paid a significant fee to sign him, but has struggled for game time in Paris under Luis Enrique and has instead spent the past two seasons out on loan, first at Stade de Reims and then at Sporting Braga.
At Braga last season he was a regular, making 39 appearances in total and helping the Portuguese side reach the Europa League semi-finals.
Espanyol's move for Moscardo is their third piece of business this week, following the arrivals of Hartman and Calatrava, and adds further competition for places in a midfield already containing Urko Gonzalez de Zarate, Edu Exposito and Pol Lozano.
The deal does not include a purchase option, meaning Moscardo will return to PSG regardless of how his season in Spain goes, though the loan gives him a chance to build on the experience gained during his temporary stints in France and Portugal.
Espanyol will cover Moscardo's wages for the duration of the loan, a common arrangement in deals of this kind.
He had also attracted interest from elsewhere in La Liga, along with clubs in Italy and Germany, before opting for a move to Barcelona in agreement with PSG. Since arriving in Paris in January 2024, Moscardo has yet to make his first-team debut for the French champions, with his development instead entrusted to a series of loan spells as he continues his progression through European football.
He was part of PSG's squad for last summer's FIFA Club World Cup in the United States, though he did not feature, before being sent to Braga for the season just finished.