I pulled out the ignition lock, sprayed some WD40 and cleaned the seat.
For now, the problem has not returned.
We hope everything goes well.
In the meantime, I took advantage of the checks on the electrical system to replace the electric actuator of the entrance door.
Unfortunately, the original spare part is now unavailable and I had to spend a couple of hours to adapt a universal actuator for cars.
The original seemed much more robust than the replacement, unfortunately we have to settle for it.
For now, the electronic lock has started working perfectly again, even with the remote control.
Thanks for your advice.