CITROËN DS 4 Handbook page 164

Manual child lock
Mechanical system to prevent opening of the rear door using its interior control.
The control, red in colour, is located on the edge of each rear door. It is identified by a symbol
marked on the bodywork.
Locking
F Using the ignition key or the integral key,
depending on version, turn the red control
as far as it will go:
- to the left on the left-hand rear door,
- to the right on the right-hand rear door.
Unlocking
F Using the ignition key or the integral key,
depending on version, turn the red control
as far as it will go:
- to the right on the left-hand rear door,
- to the left on the right-hand rear door.
Do not confuse the child lock control,
which is red, with the back-up locking
control, which is black.