The accident brings to at least six the number of people killed in collisions involving electric scooters since the zippy devices began popping up in ride-sharing schemes around the country in mid-2019.
Sunday's incident took place in the early hours of the morning on the banks of the Garonne river in central Bordeaux.
The male scooter rider was pronounced dead at the scene. His female companion, aged 18, was rushed to hospital in critical condition.
The last few months have seen a rash of deadly accidents involving the widely popular two-wheelers, which have revolutionised urban mobility.
Nearly all the victims were scooter riders in their twenties but the first fatality was an 81-year-old man, who died after being knocked over by a scooter in the Paris suburb of Levallois.