The 26-year-old moves to England for an undisclosed fee, subject to international clearance, after three years in Ligue 1.
Tettey becomes manager Chris Hughton's seventh signing of the summer and, although clearance will not be received in time for the match at QPR, Tettey will be present at Carrow Road as the Canaries look to put their shocking start to the season against Fulham last week behind them.
Tettey, who plays as a defensive midfielder, made a total of 82 appearances in all competitions for 'Les Rouges et Noirs' including 10 appearances in the Europa League last season.
Hughton told the club's official website: "I'm delighted to have Alexander on board and I firmly believe he will be a valuable asset for us. He's a very good player with international experience, and he's at a good age for us."
Although born in Accra, Ghana, Tettey is a naturalised citizen of Norway and started his career at the country's most successful team Rosenborg, with 22 league titles to their name.
Tettey joined the club in 2003 and eventually went on to captain the side in the absence of club legend Roar Strand, eventually spending six years with 'The Troll Kids'.
He made his senior debut in 2007 and went on to amass 89 appearances, including 12 in the Champions League, before leaving for Rennes in 2009.
He also scored an impressive 12 goals from the heart of midfield.
Tettey has represented Norway at under-18, 19 and 21 levels and has 14 full caps for the senior side making his debut in the 2-1 win over Argentina in August 2007.
Source: PA
Source: PA