Ok some updates, unfortunately I still dont know what was installed in my car.
The switch is connected to a major set of wire, wrapped in black duct tape.
On one side (in direction of the central console) there is a BIG connector : the device that this switch is supposed to control was probably plugged in it ! then from this connector a set of wire is going behind the central console.. is it going to the ECU ? I don't know.
On the other side (in direction of the steering wheel and the fuse box), the switch is connected to a relay, which is connected to the fuse box and also the clutch switch. I tried immediately to start the car without pushing the clutch but
pressing the switch, failed, the switch has no effect on the clutch .
Some pictures to show you the different parts.
Any idea (realistic please
) ? What kind of device can be plugged and needs to interact with the clutch sensor ?