 He turned professional in 1957, when he beat Albert Bouvet to win the world pursuit championship at Rocourt, Belgium.On the advice of his team manager, Raphaël Géminiani, and his agent, Daniel Dousset, Rivière attempted Ercole Baldini's hour record on 18 September 1957 at the Vigorelli track in Milan.He was still in national service in the army at Joinville, near Paris, although in a battalion which allowed the country's top athletes to train at public expense.