The 26-year-old has played 25 Tests for the All Blacks.
"I'm excited to announce that the next chapter of my rugby career will be with La Rochelle in France," he said.
"It was an extremely hard decision to make, but I feel it is the right one for my family and myself. I've always wanted to play rugby in New Zealand and to represent teams like Waikato and the Chiefs which is where my family comes from. It was a childhood dream of mine to become an All Black and it has been a privilege to represent my country."
