As you walked around the Stade de France before the gold medal match, the carnival atmosphere was obvious.

Home fans in the blue, white and red of the Tricolore many in fancy dress, comedy wigs and face paint - made merry as they counted down to the main event which they dreamed would lead to French glory.

But when you actually spoke to a few away from the fun, it was clear there was a sense of concern.

France might not win. In fact, they probably wouldn't so many thought.

That was because France were the underdogs against two-time defending champions Fiji, who had never previously lost an Olympic men's sevens game.

South Africa beat Australia 26-19 to take the bronze medal, and then the test of French resolve arrived.

Those fears of worried home supporters seemed to be justified when the Pacific Islanders threatened to spoil the party as Joseva Talacolo went over inside two minutes.

But belief among the French players remained.

Before half-time they were level thanks to Jefferson-Lee Joseph powering through the middle and diving between the posts, almost like he was competing at the Aquatics Centre over the road.

Then Dupont arrived.

Fuelled by the energy of the crowd, and the second-half impact of their talisman, Les Bleus moved ahead when English-born Grandidier finished off Dupont's handiwork.

Grandidier was born in London, grew up in Bromley and learnt to play rugby in Orpington.

When still a teenager, the winger decided to take advantage of his French mother's heritage and try his luck across the Channel.

"To be completely honest, no-one was picking me up in England - no professional academies anyway. That's what I really wanted," said Grandidier, now 24, who earlier this year joined French Top 14 side Pau.

He told BBC Sport: "I found out France had a system that allowed you a bit more time to break out on to the scene, so I was like, 'you know what, screw it, I've got nothing to lose, this is what I want to do'.

"So I decided to chase it and pursue that dream."

Now Grandidier and the rest of the French sevens team are living the dream, and what the hosts will hope becomes a summer gold rush is up and running.