CITROEN BERLINGO MULTISPACE Handbook page 104

Safety
Child lock
This prevents the sliding side doors from being
opened from inside.
Manual
A label shows you the position of the lever and
the child lock status.
F Open completely, while passing the point of
resistance.
F Tilt the lever located on the rear section of
the door.
102
Electric
F With the ignition on, press this button.
Indicator lamp on = child lock active.
This system is independent of the central
locking control.
Always remove the key from the ignition
when leaving the vehicle, even for a short
time.
It is recommended that you check the
activation of child lock each time you
switch on the ignition.
In the event of a violent impact, the child
lock is disabled automatically.
https://www.automotive-manuals.net/