Mundo Deportivo reports that Freire will join Barcelona's youth setup once bureaucratic rules allow him to sign, having already featured in several tournaments with the club's junior sides in recent months.
Freire cannot officially sign until he turns 16 next week, at which point he is expected to join the club's juvenil squad, with the possibility of minutes at reserve-team level further down the line.
The move continues what has already been an active summer of academy recruitment for Barcelona following the arrivals of Mikael Baza and Jesse Bisiwu.
A versatile midfielder capable of playing across the attacking positions behind the striker, Freire was born in Portugal before moving to Luxembourg as a child. He spent last season with Racing FC Union Luxembourg, where he played in the UEFA Youth League, and has represented both Portugal and Luxembourg at under-15 level internationally.
For now, he appears to have settled on representing Portugal, having trained with the country's under-17 squad.
The signing continues a familiar pattern for Barcelona, who have built a reputation in recent years for scouring Europe's smaller footballing nations for emerging talent before they attract attention from bigger clubs closer to home.
Freire's dual eligibility for Portugal and Luxembourg, along with his time developing outside either country's traditional academy pathways, made him a player Barcelona were able to move for relatively quietly compared with more high-profile targets.
Barcelona's youth system has become an increasingly important pipeline for the first team in recent years, with several academy graduates having broken into Hansi Flick's squad, and the club continues to invest heavily in scouting networks across Europe to identify players at an early age.
Freire's arrival adds further depth to a midfield generation already considered among the most promising in the club's youth ranks, with academy staff said to be particularly impressed by his versatility and composure on the ball for a player of his age.