With the under-17 team, Sissoko's playing time increased as France attempted to qualify for the 2006 UEFA European Under-17 Football Championship. He made his debut as a substitute on 2 November 2005 in the team's opening competitive match against England. On 26 February 2006, Sissoko scored his first youth international goal in the team's second group stage match of the Algarve Cup against the Netherlands. In the team's next group stage match against Portugal, Sissoko scored again in a 3–1 victory. In UEFA competition, Sissoko and the team, composed of players such as David N'Gog, Gabriel Obertan, Adel Taarabt, and Grégory Sertic, failed to qualify for the 2006 UEFA European Under-17 Football Championship, due to their second-place finish in the Elite Round portion of the competition. With the under-18 team, Sissoko appeared in all eight matches the team contested as France nearly went undefeated losing their only match 1–0 to Germany in Kehl.