Buffet competed in his first European Cup race in the 2008/09 season and it took him four years to finish in the top 10 for the first time. Buffet celebrated his first victory in the European Cup on 16 December 2015 in the Slalom in Obereggen. This was followed by another slalom victory in Val-Cenis on 4 January 2016. ER took part in the 2011 Junior World Championships in Crans-Montana, where he played no part in the fight for the medals, however. His best placing was 12th in the slalom.
Buffet made his debut in the Alpine Ski World Cup on 24 January 2012 in Schladming, where he failed to qualify for the 2nd round. He scored his first World Cup points on 13 December 2015 with 22nd place in the slalom in Val-d’Isère. In the 2015/16 European Cup season he won the slalom classification. He achieved his best result in a World Cup slalom on 15 January 2017 with 9th place in Wengen.
Buffet was never able to equal that result.
He ended his career in April 2020.