CITROËN DS 5 Handbook page 156

Rear wiper
If a significant accumulation of snow
or ice is present, or when using a
bicycle carrier on the boot, deactivate
the automatic rear wiper via the
configuration menu.
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 configuration
menu.
This function is activated by default.
Windscreen and headlamp
wash
F Pull the windscreen wiper stalk towards
you. The windscreen wash then the
windscreen wipers operate for a fixed
period.
The headlamp washers only operate when the
dipped or main beam headlamps are on,
with the vehicle moving.
To reduce the consumption of the fluid by the
headlamp washers, they operate only with
every seventh use of the screenwash or every
25 miles (40 km) during a given journey.