The former Connacht player lined out with Sexton at U21 level for Ireland in a Six Nations and World Cup campaign before moving to France. He initially struggled before discovering the key nuances to succeeding as a professional player in France.
“I reckon it won’t be a massive difference in terms of learning a new game plan,” he said, “but at 10 there are other things which are vital to succeed here.
“When I first came over the biggest problem was communication on the pitch. You can do as much French as you want in the Leaving Cert but bossing 20 stone guys around the field in the heat of a game is a very different experience.
“I struggled at the start, the same way every other foreigner in that position does. Shane Geraghty went to Brive and struggled, Dan Carter got injured and struggled, James Hook is struggling at Perpignan. You need to get comfortable with the language first and foremost.”
With Laurent Labit and Laurent Travers due to take over the club’s managerial reins on April 1, leaving Castres in a high-profile switch, Sexton will find a club in transition but one where there is no guarantee he will have a starting spot.
“In Metro there’s not a huge amount of foreigners and I know the two Laurents are keen on French players.
“They used to coach here and everyone still speaks very highly of them.
“Top 14 is a long hard slog so even at Metro they have three top class out-halves. Olly Barkley, Juan Martin Hernández and a French guy called Jonathan Wisniewski are already there.
“My first year, I considered myself outgoing, but without a sob story I felt on my own. You have to stick out and be proud of yourself and it will get better and better and easier and easier. He’s an intelligent guy so I’d back him to do it.”
There’s also the president. Property guru Jacky Lorenzetti has a reputation for demanding victories from his players and if they don’t keep the Parisian fanbase happy, they can expect an angry visit from the man worth €90m.
“Having experienced the provincial set up in Ireland, where there’s a lot of stability, he will find it’s different in France. There’s no loyalty to the clubs and there’s a lot of player turnover. The president in Metro spent a lot of money getting them to where they are and if they lose a match he feels they should have won they can expect a visit.
“It’s the latin temperament where it’s all highs or lows.
“Personally I’m delighted for [Sexton]. It shows he’s a good brave lad. He could have stayed with Leinster and been a hero but he’s going on an adventure.”