He made his breakthrough in the 2013–14 season, reaching the quarter-finals at the La Coruña Grand Prix, the Havana Grand Prix and the Tokyo World Cup. He was selected into the national for the European Championships in Strasbourg, but he lost in the first round to teammate Julien Mertine in the individual event. In the team event France defeated the Czech Republic and Russia before prevailing over Italy, allowing Simon to win his first gold medal in a major event. At the World Championships in Kazan he defeated World No.7 Alexander Massialas before ceding in the table of 16 to Alexander Choupenitch of the Czech Republic. In the team event France defeated Russia in the semi-finals and proceeded to crush China to earn the world title.