[2] Brito was born in Covilhã, Portugal, but acquired French nationality and was a France youth international having earned caps with the under-15 and under-16 teams.

At the age of six months, his family moved to France after his father, Quim Brito, a football player, signed with FC 4 Rivières 70, an amateur club located in Dampierre-sur-Salon in the Franche-Comté region.

He quickly rose through the ranks of the academy and established himself as one of the club's top prospects in his age group alongside fellow midfielder Serdar Gürler, striker Cédric Bakambu, and goalkeeper Pierrick Cros.

[9] Also during the season, Dias was a part of the Sochaux under-19 team that reached the final of the Coupe Gambardella, the country's prestigious youth cup competition.

Dias converted his penalty, however, early failed attempts by Gürler and Clément Giraud dashed the team's hopes.

[13][14] Midway through the 2009–10 Ligue 1 season, Dias, alongside Gürler, began integrating with the first team after manager Francis Gillot announced his desire to give the club's youth talent an opportunity.

Benfica wanted the player to remain at the club, however, due to being under contract with Sochaux, he returned to France for pre-season training.

In 2010, Dias announced his intent to represent Portugal at international level and confirmed his decision by declining the opportunity to attend a training camp for future France national under-21 players.