After centre backs William Gallas, Sol Campbell and Mikael Silvestre all left in the summer of 2010, Arsène Wenger drafted in Sebastien to reinforce his defensive options.
The vastly-experienced international, who has represented France over 20 times, made 32 appearances during a low-key but solid debut season in the Premier League.
His knowhow was an asset to the Arsenal back-line alongside the younger pair of Johan Djourou and Laurent Koscielny.
Sebastien was part of AS Monaco's impressive Champions League run in 2004, helping the side reach the Final by beating Real Madrid and Chelsea en route.
