When I saw the Micra at the Ottawa auto show, I was surprised to see where the spare tire is located:
(Click to zoom.)
This picture was taken from the left, rear of the car, shot facing forward. It appears to be a space saver. To release the bracket that holds the wheel, there's a bolt inside the hatchback (it goes through the floor). You use the wheel wrench to loosen the bolt:
Attachment 174
This is the first time I've seen a spare tire mounted underneath a car. Very common on trucks, but cars? Not so much!