This is a photo from two years ago, i stood there for a good minute wondering how the hell and why this weird cycle path was there. It is in southern France, on the climb to Col d'Ecre, bit north of Nice.
A pullout area to allow backed up vehicles to pass?
It's strange that it's on the downhill side and not the uphill, though!
Other guesses: Brake check area (stop and let brakes cool...); U-turn area as we sometimes see for the 'j-turn' configuration; The pullout is for uphill cyclists but they have to make a u-turn to use it.