Flameng competed in four cycling track events at the 1896 Summer Olympics, on the 8th April 1896, he competed in the 100 km race which was 300 laps of the Neo Phaliron Velodrome, out of the nine starters on two finished with Flameng winning the gold medal 11 laps ahead of second place Georgios Kolettis from Greece. After a couple of days rest he was back in the saddle at the Velodrome competing in three more events, he won a silver medal in the 10 km race finishing just behind fellow countryman Paul Masson, he also won the bronze medal in the sprint race, which was six laps around the Velodrome, and finally he finished in joint fifth place in the time trial.
In 1898 he joined the 8th Infantry Division (France) to do his National Service, he then joined the French Air Force in 1914 as an observer before becoming a military pilot in 1916, on the 21st June 1916, while on a mission on Verdun his plane was hit and although he was hit in the head with a bullet and his crew killed he still managed to get his plane back to base, after being hospitalised he returned to his squadron and was promoted to sergeant before transferring to the Group of Training Division. Sadly, on the 12th January 1917(*), while trialing a new Sopwith biplane near Ève, Oise, there was a technical incident forcing the plane to crash to the ground killing Flameng.
- More information (in Dutch) on http://nl.renners-in-de-grote-oorlog.wikia.com/wiki/Léon_Flameng.
- More information (in French) on http://fr.cyclistes-dans-la-grande-guerre.wikia.com/wiki/Léon_Flameng.