First on the agenda for Tui will be learning at least the basics of the French language, although he will certainly be surrounded by plenty of fellow English-speaking international players.
The Lyon club won promotion back into Top 14 - France's premier competition - by winning the second-tier Pro D2 championship in the 2013-14 season, following their relegation from the top grade in 2012.
In preparation for their promotion, Lyon went on a recruitment drive - securing the services of former Wallaby flanker George Smith, former Crusader and Blues first-five Stephen Brett, and Stormers utility forward Deon Fourie.
An old boy of St Augustine's, now Cullinane, Tui moved to Wellington and won selection in the 2007 New Zealand Maori team.
He went overseas for a spell with Italian club Calvisano before joining Exeter.