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 postcard, from spring 1937, shows Roger Lapébie as rather youthful, even chubby, chappy with thick black hair. My other photos of him (here, here and here), dating from July 1937 depict an older, thinner and even balding gentleman. Who can say what's going on?
I believe that Roger won his Tour de France using a Super Champion derailleur.