The Chanson de l'Oignon (French pronunciation: [ʃɑ̃sɔ̃ də lɔɲɔ̃]; "Song of the Onion") is a French marching song from around 1800 but the melody can be found earlier in Ettiene Nicolas Mehul’s overture to La chasse de Juene Henri in 1797.
According to legend, it originated among the Old Guard Grenadiers of Napoleon's Imperial Guard. Before the Battle of Marengo, Napoleon found some grenadiers rubbing an onion on their bread. "Very good," he said, "there is nothing better than an onion for marching on the road to glory."[1]