The incident occurred between 1.30 and 2.30pm, according to witnesses. Police were called to the scene, as well as a tow truck to rescue the vehicle from the river.
The Moselle fire brigade were not required, and no injuries were reported.
A spokesman for the Metz-Plage campsite said he had not witnessed the vehicle plunging into the Moselle, saying a number of other cars had blocked their view of the incident. He believed it to have been a manoeuvre gone wrong, saying the curb was quite high and it would be difficult for a vehicle to end up in the water due to not applying the handbrake.
The camper van, which was parked in the public car park alongside the Moselle, belonged to Dutch tourists.
