CITROËN DS 5 Handbook page 108

Emergency braking
The emergency braking must only be used in
exceptional circumstances.
In the event of a failure of the main
service brake or in an exceptional
situation (e.g. driver taken ill, under
instruction, etc) a continuous pull
on the control lever A will stop the
vehicle.
The DSC system provides stability when
braking during emergency braking.
If the emergency braking malfunctions, the
message "Parking brake control faulty" will be
displayed.
If a failure of the DSC system is signalled
by the illumination of this warning lamp,
then braking stability is not guaranteed.
In this event, stability must be assured
by the driver by repeating alternate "pull-
release" actions on the control lever A.
Special situations
In some circumstances (engine start...),
the parking brake may adjust the level
of application itself. This is normal
operation.
To move your vehicle a few centimetres
without starting the engine, with the
ignition on, press the brake pedal and
release the parking brake by pulling
then releasing the control lever A.
Complete release of the parking brake
is indicated by the warning lamps in the
control lever A and in the instrument
panel going off and by the display of the
message "Parking brake off".
To ensure correct operation, and so
your safety, the number of successive
applications and releases of the parking
brake is limited to eight cycles.
If used excessively, you are alerted by
the message "parking brake faulty" and
a flashing warning lamp.