Ian Madigan and Marty Moore are the prime examples of that since they left Leinster for France and England. Sexton, irreplaceable to Ireland at out-half, has been the only emigre kept on board by the national squad during his years offshore.

Still, it made for a tough two years.

The 32-year old played his first game in pre-season for Racing just four weeks after his arrival in Paris off the 2013 British and Irish Lions tour and continued to burn the candle at both ends for club and country through that first season.

“So there's no break in the season whereas if you're in Racing and not playing international rugby there'll be loads of breaks because you'll have the two-week break at Christmas, a week break in November, you'll probably get time off during the Six Nations.

“So as a non-international playing player it's not so bad. It's when you have to try and do both is when you run into difficulty. So if I was to advise anyone, I'd say wait until the end of your international career before you decide to go over, but that's in hindsight.

“I made the opposite decision.”

Sexton has admitted before, and did so again on Tuesday afternoon at an Aer Lingus promotion, that he found the juggling act “very tough” It had been a “big call” for Zebo to leave at the age of 27, he added, and just two years out from the next World Cup.

“But I'm sure he's weighed all that up. And, again, everyone's circumstances are different. The decisions I made at the time maybe are totally different to what Simon is going through.

“I'm sure it was very tough either way, because he's definitely Munster through and through. It would be good to see him back here in a couple of years. I don't know how long he's signed for.”

If it is Racing that Zebo is to join then Zebo will find a very different landscape to that which Sexton knew. Gone will be the decrepit old home that is the Stade Olympique Yves-Du-Manoir, to be replaced this very month by the spage-age U Arena.

His loss to Irish rugby will be considerable.

Zebo is Munster’s all-time record try scorer and he has become a pivotal and regular figure in Ireland’s back three of late having taken some time to convince Schmidt that he had the requisite defensive abilities to compliment his attacking brilliance.

“Simon is a great character to have around the environment, whether it’s with Munster or Ireland,” said Sexton. “I know you said it took a while but him and Joe seemed to always get on well. Once Simon has been doing what Joe wanted of him he’s got picked because he’s so talented and so good.

“From that point of view, I think personally Simon is only going to get better. It will be a loss of course for Munster and Ireland but we’ve got so much good talent in the back three coming through. Not that it won’t be a loss, I’m sure it will be harshly felt in Munster.”