According to another Twizy owner there is a pedestrian warning bleeper. This emits a beeping sound to warn people you are coming. This is not in the owners hand book downloadable from the Renault site. So if your car starts to beep and it is not an error check you have not caught the switch shown here.
[attachment=0:4x0u2uyo]Twizy pred buzzer.png[/attachment:4x0u2uyo]