CITROEN DS5 Owner's Handbook Manual page 164

Installing child seats attached using the seat belt
In accordance with European regulations, this table indicates the options for installing child seats secured using a seat belt and universally approved (a)
in accordance with the weight of the child and the seat in the vehicle:
Seat
Front passenger seat ( c ) with c
height adjustment
Outer rear seats
Centre rear seat
a: universal child seat, child seat that can be installed in all vehicles using a seat belt.
b: group 0, from birth to 10 kg. Shells seats and baby carriers cannot be installed in the front passenger seat.
c: consult the legislation in force in your country before installing your child on this seat.
U: seat suitable for the installation of a child seat secured using a seat belt and universally approved, "rearwards-facing" and/or "forwards-facing".
U (R): same as U, with the passenger seat adjusted to the highest position and as far back as possible.
X: seat position not suitable for installation of a child seat for the weight class indicated.
Weight of the child and indicative age
Under 13 kg From 9 to 18 kg
(groups 0 (b ) and 0+)
Up to approx 1 year 1 to 3 years approx
U (R)
U
X
From 15 to 25 kg
(group 1) (group 2)
3 to 6 years approx
U (R) U (R)
U U
X X
From 22 to 36 kg
(group 3)
6 to 10 years approx
U (R)
U
X