Bassong moved to White Hart Lane in 2009 for £8 million but fell out of favour last season, spending the second half of the campaign at Wolves.
The Cameroon international tweeted: "Morning tweeps!! I've been officially transfered to Norwich today! 3 years deal! Another chapter in my football life!
|11/1||Tottenham are 11/1 with Bet365 to beat West Brom 3-1
Bassong was first introduced to English football at Newcastle United, who signed him from Metz in 2008. The Frecnh-born defender was unable to prevent the Magpies' relegation from the top flight, but impressed enough to earn a move to Spurs.
The defender made 72 appearances in three seasons in north London and has featured 15 times for Cameroon's national side.
He becomes Chris Hughton's second centre-back signing in recent weeks, following the arrival of Michael Turner from Sunderland.
The Carrow Road boss told the club's official website: "Sebastien is a player that I have known well since my time at Newcastle and I’m delighted to have brought in someone with the Premier League experience he has got.
"He will give us power and pace at the back and again add to the competition in the squad."