I found a scooter near of paris in dechettery. He was in very bad condition (arm broken !) but he startup after charging step.
For information i tried to flash the original dashboard in place on rental scooter by following the process : https://hackmd.io/s/Bki2fcWwE
i was able to connect and flash the dash with the firmware created on : ninebot.scooterhacking.org
After the installation of the flashed dashboard the scooter was stuck... Dashboard black out.
The motorboard is like a lyft board with more juice to powered the GPS / cellular.
i will try some additional checks and let you know. i made an order for an original Ninebot dashboard even if the scooter is unusable...