CITROEN DS3 Handbook page 142

Rear wiper
If a significant accumulation of snow or
ice is present, or when using a tailgate
bicycle carrier, deactivate the automatic
rear wiper via the multifunction screen
configuration menu.
B. Rear wiper selection ring:
park,
intermittent wipe,
wash-wipe (set duration).
Reverse gear
When reverse gear is engaged, the rear wiper
will come into operation if the windscreen
wipers are operating.
Programming
The function is activated or deactivated via the
vehicle configuration menu.
This function is activated by default.
Windscreen wash
Pull the wiper stalk towards you.
The windscreen wash, then the windscreen
wipers, operate for a pre-determined time.