Before he reached the world championship he was joining the CDM French motorsport school.

Masbou had a good debut season, with a best result of fifth in the Dutch TT, having run in the leading group throughout.

For 2008 he joined the new Loncin team, struggling to make this bike competitive and scoring four points.

At the 2014 Czech Republic Grand Prix, Masbou achieved his first victory at World Championship level after prevailing in a 17-rider lead battle, holding off Enea Bastianini and Danny Kent on the final lap.

After failing to score a single point in nine races he was replaced by Albert Arenas ahead of the Austrian Grand Prix.