The Postbus (2017, Euro 6 diesel) has the advantage of being a car subject to the usual regulations. You can park it anywhere and then sleep in it overnight. It's economical (5.5 liters of diesel per 100 km) and offers the lowest toll rate.
A microcamper offers much more flexibility than a campervan. Small country roads are never an obstacle, and you can park at any pitch. You also have more comfort and shelter than with a tent. You're not really noticeable, with minimal setup and dismantling, two beds made, and you can quickly set up and go.
For a bit more comfort and space, you can pitch a bus tent at a campsite, where you can set up your cooking area, table and chairs, and chemical toilet. Then you can go on a trip with the Postbus without wasting time, and even cook a meal somewhere in nature, drink something cold from the mini-fridge, and even take a nap on the comfortable bed.
You can also take two bicycles: one on the bicycle carrier (max 17 kg, so no e-bikes) and one (e-bike) in the car with the bed folded up.
There is ample space under the bed for your luggage, and if you use the supplied plastic containers for your clothes, you can quickly get to your belongings and tidy them away just as quickly.
What is provided: blackout curtains and blinds, cooking and eating utensils, small gas stove with one burner, bucket with lid, 2 tables, compact chemical toilet if required (smallest Portapotti model), extension cord and Euro camping adapter, bottom sheet, spacious "bus tent" (see photos), drinking water jerry can (10 litres).
The living space in this campervan is very limited. Sitting upright in the bed is impossible. The bed is 185cm long and 120cm wide, but taller people can stick their feet out when the front seats are folded flat.
PS:
1/ The insurance only covers drivers from the age of 26, provided you have held a driving licence for three years!
2/ The French Post Office installed a speed limiter that limits your speed to 110 km/h on the motorway, but without any loss of power: so you can overtake safely on secondary roads.
3/ The van has air conditioning, cruise control, automatic transmission, and a cigarette lighter in the rear.