CITROEN DS3 Owner's Handbook Manual page 36

Deactivation indicator lamps
If one of the following indicator lamps comes on, this confirms that the corresponding system has been switched off intentionally.
This is may be accompanied by an audible signal and a message on the multifunction screen.
Warning lamp
Passenger's
airbag system
ESP/ASR
is on Cause
fixed. The control, located in the glove box,
is set to the OFF position.
The passenger's front airbag is
deactivated.
In this case you can install a
"rear facing" child seat.
fixed. The button, located at the bottom
left of the dashboard, is pressed. Its
indicator lamp is on.
The ESP/ASR is deactivated.
ESP: electronic stability programme.
ASR: anti-skid regulation.
Action/Observations
Set the control to the ON position to activate the
passenger's front airbag.
In this case, do not fit a child seat in the rear-facing
position.
Press the button again to manually reactivate the
ESP/ASR. Its indicator lamp goes off.
From approximately 30 mph (50 km/h), the system is
reactivated automatically (except for the 1.6 litre
THP 150 and RACING engines).
The ESP/ASR system is activated automatically when
the vehicle is started.