In March 2013, FIFA named Gassama as one of the fifty potential referees for the 2014 World Cup. On 15 January 2014, FIFA announced that he would be one of the 25 referees for the tournament. His assistants were announced to be Evarist Menkouandé and Felicien Kabanda.[8] He officiated the third group stage match in group B between the Netherlands and Chile on 23 June 2014. He officiated the 2015 Africa Cup of Nations Final match on 8 February 2015 between Ghana and Côte d'Ivoire.
On 29 March 2018, FIFA announced that he had been selected to officiate some matches at 2018 FIFA World Cup along with Jean-Claude Birumushahu and Marwa Range as assistant referees.[10]
FIFA announced that he had been selected to officiate some matches at 2022 FIFA World Cup Qatar.[11]