CITROËN C4 Picasso Owner's Handbook Manual page 284

Practical information
Lamps on the tailgate
Identify the failed bulb.
Open the boot.
Remove the access cover.
286
Remove the three lamp fixing screws A.
Disconnect the lamp connector.
Carefully remove the lamp from its housing.
Turn the bulb holder a quarter of a turn
anti-clockwise and pull the bulb out.
Change the bulb.
For reassembly, carry out these operations in
reverse order.
Model with LED lamps
Model with conventional bulb lamps