The facts took place on Monday, around 11:30 p.m., on an avenue in the sensitive district of Neuhof, located in the south-east of the city of Strasbourg.
Police said an 18-year-old on a scooter was chasing a 22-year-old man who was on foot.
The latter kicked the scooter to free itself, causing his pursuer to fall.
The 18-year-old, who was riding without a helmet, hit a sidewalk with his head.
When the firefighters arrived on the scene, the young man on the ground was "in cardio-respiratory arrest".
Transported to hospital, he was declared dead on his arrival at the Hautepierre hospital center.
For the moment, the police evoke “a dispute between several people” without knowing precisely the nature of this one.
In the meantime, two people were taken into police custody: the young person suspected of having dropped the scooter and a man who accompanied the victim.
An investigation, entrusted to the departmental direction of public security of Bas-Rhin, was opened for "theft, threats and violence resulting in death without intention of giving it".