CITROEN C4 Cactus Handbook & Instructions page 224

Checks
Screenwash fluid level
Top up the level when necessary.
Fluid specification
For optimum cleaning and to avoid freezing,
this fluid must not be topped up or replaced
with plain water.
In wintry conditions, it is recommended that you
use an ethyl alcohol or methanol based fluid.
222
Diesel fuel additive level
(Diesel with particle filter)
The additive reservoir low level is
indicated by fixed illumination of
this warning lamp, accompanied by
an audible signal and a message
that the particle filter additive level
is too low.
Topping up
The reservoir must be topped up without delay
by a CITROËN dealer or a qualified workshop.
Used products
Avoid prolonged contact of used oil or
fluids with the skin.
Most of these fluids are harmful to
health or indeed very corrosive.
do not discard used oil or fluids into
sewers or onto the ground.
Take used oil to a CITROËN dealer or
a qualified workshop (France) or to an
authorised waste disposal site.