The defender has signed a two-and-a-half-year contract at Stadium Municipal.
Kana-Biyik joined Rennes from Le Havre in June 2010 but, after initially becoming an integral part of their defence, persistent thigh problems last season saw the former Cameroon international's influence diminish. He was also suspended for confrontations with supporters in May 2014.
The 25-year-old has failed to make a Ligue 1 appearance this season after being frozen out by coach Philippe Montanier.
Toulouse will lose four players to the upcoming Africa Cup of Nations and the arrival of Kana-Biyik gives them defensive reinforcements.
A statement on the club's website read: "Toulouse Football Club is pleased to announce the signing of central defender Jean-Armel Kana-Biyik.
"After passing the traditional medical tests, the defender has signed a two-and-a-half-year contract.
"To compensate for departures to the African Cup of Nations of four Toulouse players (Steeve Yago, Issiaga Sylla, Tongo Doumbia and Jean-Daniel Akpa Akpro), the recruitment team decided to expand its workforce with players likely to adapt quickly to the collective of the team.
"The experience accumulated by Jean-Armel Kana-Biyk in Ligue 1 will be an invaluable asset to accompany a youthful Toulouse defence."
