At the age of thirteen, Le Guen joined the youth academy of professional club
Brest. In the 2023–24 season, while an under-19 player, he participated in his first training sessions with the club's first team. He participated in the pre-season ahead of the 2025–26 season, and made his professional debut as a substitute in a 3–1 defeat away to
Lens on 29 August 2025. On 21 January 2026, Le Guen signed a professional contract with Brest until June 2029. == References ==