The men's marathon was a track & field athletics event at the 1900 Summer Olympics in Paris.

Decades later, after his true nationality was determined, the Grand Duchy of Luxembourg lodged a complaint with the International Olympic Committee and petitioned to change the Olympic record of Théato's nationality; this complaint was rejected in 2004.

[1] In 2021, the IOC online data and medal table for the 1900 Games were changed to reflect medalists' nationalities in this and eight other events, including for Michel Théato.

While 20 runners entered, only thirteen started, with seven finishing the race: one dropped out during the four laps around the track that preceded the road running.

Fast took the lead, but had tired himself trying to keep pace with the Frenchman, and was passed by Théato and Champion before the end.