CITROEN DS3 Handbook page 178

Child seat in the front*
"Rearward-facing"
When a "rearward-facing" child seat is installed
on the front passenger seat, adjust the seat
to the intermediate longitudinal and highest
position, with the backrest straightened.
The passenger airbag must be deactivated.
otherwise, the child would risk being
seriously injured or killed if the airbag were
to inflate.
* R efer to the current legislation in your country
before installing a child seat on this seat.
"Forward-facing"
When a "forward-facing" child seat is installed
on the front passenger seat, adjust the
vehicle's seat to the intermediate longitudinal
and highest position with seat backrest
straightened and leave the passenger's airbag
activated.
Ensure that the seat belt is correctly
tensioned.
For child seats with a support leg,
ensure that the support leg is in stable
contact with the floor. If necessary,
adjust the passenger seat.
Passenger seat adjusted to the intermediate
longitudinal and highest position.