He was found guilty of cheating by the French Chess Federation (FFE) and sanctioned in 2012 by not being allowed to participate in FIDE tournaments for 2 years and 9 months.

He played as the first reserve for France in the European Team Championships 2009 held in Novi Sad, Serbia, scoring +4 =4 -1.

In October 2010, Feller scored 6/9 (+5 =2 -2)[5] during the 39th Chess Olympiad and won the Gold medal for best individual performance on board 5.

However, the FFE accused Feller, along with French players GM Arnaud Hauchard and IM Cyril Marzolo,[6] of cheating during the Olympiad.

Moreover, at that time I spoke in private conversations, which were repeated, of countable irregularities of the French Chess Federation (of which the precise details will be given later), which angered the FFE President.

[vague][citation needed] In July 2012 the FIDE Ethic Commission sanctioned all three players and ruled "Mr. Sébastien FELLER has to be sanctioned with the exclusion from the participation in all FIDE tournaments, as a player or as a member of a national delegation, for a period of 2 (two) years and 9 (nine) months, starting from the 1st of August 2012".