I'd be disappointed to see him leave, but in every article I've read about him it's clear that he isn't the average Rugby player. He wants to travel the world and play at the highest level. I suspect he will be one of those players who doesn't stay anywhere for too long and ends up playing in all the major leagues around the world. He's only really been at Wasps for around 12 months, so it's not like we have invested the same level of resources into him as we did with Billy Vunipola for example.
I suspect that he will get plenty of excellent opportunities next season should he stay, especially if Charlie Matthews leaves, but if he moves to France, then given the amount of time he's spent away from home I wouldn't begrudge him the chance.