"We can change very quickly our attitude on the pitch. I know that is something strange, people can't understand it, sometimes we cannot understand it ourselves. For us we have less chance than New Zealand to win the final, but if we have just one, we have to take it."
Just which French team turns up this Sunday - the Dr Jekyll who sent England packing or the Mr Hyde who lost to Tonga - is something for the oval ball gods, he reckons.
Now the manager of the national under-20 side, Sella has worked closely with coach Marc Lievremont, a man who has been one of the best entertainers off the field during this tournament. This week he publicly shamed some players as "spoilt brats" for heading out after the team's win over Wales to say nothing of his feuds with journalists and talk of player unhappiness.
But Lievremont is a man who has integrity, Sella believes, and he hopes his nation gets behind him this weekend.
He loves the symmetry of the same four teams being involved in a World Cup final 24 years after the inaugural event. No matter what happens, he's a big a fan of the Tricolors as he ever was, he said.
As for the result: "I keep that for myself. I have wishes, hopes and we must leave it for the French team. We will support them."
Still fit, he's been enjoying training runs along Auckland's waterfront and he'll pull on his boots on Friday at Ponsonby Rugby Club.
It'll be a fun game of touch for the benefit of people he is also hosting out here. He's looking forward to seeing club stalwart and former All Black Bryan Williams.
He's hoping it won't be too strenuous."I have just boots to play touch rugby - not full contact, never again," he laughed.