CITROEN DS5 Owner's Handbook Manual page 82

Repositioning the seat
backrest and cushion
Keep the seat belt guide 2 held against the
vehicle to avoid trapping the seat belt when
repositioning the seat.
Straighten the seat back 4 while refitting
the head restraints and secure it.
Check that the red indicator, located next to
the control 3 , is no longer visible.
Reposition the cushion 1.
Release the seat belt guide 2.
Put the seat belt back in place in the guide.
When repositioning the seat backrest,
take care not to trap the seat belts.