Mercedes-Benz S-Class Cabriolet 2017 Owner's Manual page 62

Weight categories
Category I: 9 to 18 kg and between approx. 9 months and 4 years
1
When using a child restraint system of size category C (ISO/R3), move the front seat to the highest position. Make sure that the seat backrest of the
front seat does not rest against the child restraint system.
Size category Equipment
D ISO/R2
C ISO/R3
B ISO/F2
B1 ISO/F2X
A ISO/F3
Occupant safety 59
Rear seat
Left, right
IL
1
IL
IUF
IUF
IUF