CITROËN DS5 Owner's Handbook Manual page 166

Direction indicators
Lower the lighting control stalk fully when
moving to the left.
Raise the lighting control stalk fully when
moving to the right.
If you forget to cancel the direction
indicators for more than twenty
seconds, the volume of the audible
signal will increase if the speed is above
40 mph (60 km/h).
"Motorway" function
Move the stalk briefly upwards or downwards,
without going beyond the point of resistance;
the corresponding direction indicators will flash
3 times.
Hazard warning lamps
Press the button, the direction indicators flash.
They can operate with the ignition off.
Automatic operation of
hazard warning lamps
When braking in an emergency, depending on
the rate of deceleration, as well as when the
ABS regulation is invoked or in the event of an
impact, the hazard warning lamps come on
automatically.
They switch off automatically the first time you
accelerate.
You can also switch them off by pressing
the button.