CITROËN DS5 Owner's Handbook Manual page 56

Lost electronic key
Visit a CITROËN dealer with the vehicle's registration document and your personal identification documents and if possible the key code label.
The CITROËN dealer will be able to retrieve the key code and the transponder code required to order a new key.
Electronic key
The electronic key is a sensitive system; do not operate it while it is in your pocket as there is a possibility that it may unlock the vehicle, without
you being aware of it.
Do not repeatedly press the buttons of your electronic key out of range and out of sight of your vehicle. You run the risk of stopping it from
working and the remote control would have to be reinitialised.
The electronic key cannot operate as a remote control when it is in the reader or even when the ignition is switched on.
Locking the vehicle
Driving with the doors locked may make access to the passenger compartment by the emergency services more difficult in an emergency.
As a safety precaution (with children on board), take the Keyless Entry and Starting electronic key when you leave the vehicle, even for a short
time.
Electrical interference
The Keyless Entry and Starting electronic key may not operate if close to certain electronic devices: telephone, laptop computer, strong
magnetic fields, ...
Anti-theft protection
Do not make any modifications to the electronic engine immobiliser system; this could cause malfunctions.
Don't forget to turn the steering to engage the steering lock.
When purchasing a second-hand vehicle
Have all of the keys in your possession paired by a CITROËN dealer, to ensure that only your keys allow your vehicle to be unlocked and started.