Kevin Ledanois, 22, became the U23 World Champion on Friday in Richmond, Virginia.
The 22 yeard older rider for Bretagne-Séché Environnement, attacked with three kilometres to go between the first and second paved section and was able to hold off Italian Simone Consonni to win in 3.54.45, while another Frenchman, Anthony Turgis, took 3rd place.
Britain's Owain Douell finished 92nd, Tao Geohagen-Hart finished 119th, with Team Sky's Alex Peters 127th with Gabriel Cullagh not finishing.
Ledanois said to his team's press office: "I do not even realise it was my dream to become world champion, then I am perhaps in a dream I could not stop crying to the podium.. .
"During the race, I waited, waited, waited. I took it on but I so want to have attacked before the last lap.
"I liked the rain in the last kilometers, I thought it made for an exciting finish.
"Anthony (Turgis ) and I almost fall into the first paved section but I pushed him to the top and it gave us some distance. Then ,I turned better than the others on the slippery roads and was able to take ten or twenty metres on Anthony, who did not have to move.
"The French team was fantastic. It was I who raised his arms and me who will have the jersey, but it's the whole team who won the world championship. "