Former South African international scrum-half Enrico Januarie will play for Top 14 side La Rochelle next season after signing a two-year contract on Wednesday.
The 33-year-old, capped 47 times and a member of the 2007 World Cup-winning squad, will join from rivals Lyon.
Both sides are battling against relegation with Lyon second from bottom, six points adrift of La Rochelle, six matches from the end of the league season.
La Rochelle also re-signed Castres’ 28-year-old centre Thomas Combezou, who played for them from 2009-11, on a three-year contract.