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.
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."
- Chris Hughton