Fabien Brau-Boirie was born in Tarbes and grew up in the Pays des Coteaux region of Bigorre.
[4] At 17, Brau-Boirie participated in the 2023 Supersevens tournament with Section Paloise, making him the youngest player in the team.
He scored a try in France's opening victory over Spain (49–12),[8][9] and played a key role throughout the competition, helping the team reach the final.
[10] Despite their efforts, the French team was defeated by England, missing out on a fourth consecutive U20 World Cup title.
[14] Fabien Brau-Boirie made his EPCR Challenge Cup debut on 12 January 2025 at Rodney Parade, where Section Paloise defeated Dragons RFC 24–15.