Following the 2013–14 season, Toupane entered the 2014 NBA Draft, but he was not selected. He then competed in the 2014 NBA Summer League for the Dallas Mavericks' affiliated team, for which he averaged 3.5 points and 2.0 rebounds per game over four games. He returned to Strasbourg following his play in the Summer League, and in the 2014–15 season, Toupane averaged 7.5 points, 2.5 rebounds and 1.4 assists per game in 42 Pro A games. Strasbourg finished as the regular-season leaders for a second straight year in 2015 and also won the French Cup and the French Leaders Cup.