Roger Lapébie won the Tour de France in 1937. It was a controversial victory, partly because this was the first year that professional riders had been allowed to use derailleurs. Many people thought the derailleur unneccessary technology, that polluted the purity of the sport. Some things are ever thus.
However the main controversy centred around Frenchman Roger Lapébie's duel with the Belgian rider Sylvère Maes. Sylvère Maes was leading the race and Lapébie was second when the race organisers took a number of decisions involving time penalties that seemed designed to deliberately favour Lapébie. During the 16th stage there was a moment of pure slapstick when the route crossed a railway line. Lapébie, in the lead, managed to get across and then the level-crossing gate was closed, perhaps deliberately, just as Sylvère Maes was approaching. While still in yellow, Maes quit the race in disgust, and took the whole of his Belgian team with him.
This unusual photo from before the start of stage 20 of the 1937 Tour, shows Roger Lapébie working on his bike. You can clearly see the Super Champion derailleur. My other photos of him are here, here and here.
(Source gallica.bnf.fr/ Bibliothèque nationale de France)