CITROEN DS4 Owner's Handbook Manual page 134

Cornering lighting
With dipped or main beams, this function
makes use of the beam from a front foglamp
to illuminate the inside of a bend, when the
vehicle speed is below 25 mph (approximately
40 km/h) (urban driving, winding road,
intersections, parking manouevres...).
with cornering lighting
without cornering lighting
Switching on
This function starts:
- when the corresponding direction indicator
is switched on,
or
- from a certain angle of rotation of the
steering wheel.
Switching off
The system does not operate:
- below a certain angle of rotation of the
steering wheel,
- above 25 mph (40 km/h),
- when reverse gear is engaged.
Programming
The system is activated or
deactivated in the vehicle
configuration menu.
The system is activated by default.