CITROEN DS3 Handbook page 108

Parking brake
Applying
F Pull the parking brake lever fully up to
immobilise your vehicle.
Releasing
F Pull the parking brake lever gently, press
the release button then lower the lever
fully.
When the vehicle is being driven,
if this warning lamp and the STOP
warning lamp come on, accompanied
by an audible signal and a message in the
multifunction screen, this indicates that the
parking brake is still on or has not been
properly released.
When parking on a slope, direct your
wheels against the pavement, apply the
parking brake and engage a gear.