Insert the key in the lock, turn it clockwise and release the seat.
Pull the seat (1) backwards to release it from the front catches and remove it.

Seat
Disassembly of the seatThe immobilizer system
For additional antitheft protection, the motorcycle is
equipped with an immobilizer, an electronic system that
locks the engine automatically whenever the ignition switch
is turned off.
The grip of each ignition key contains an electronic device
that modulates the output signal from a special ...
Refitting the seat
Note
Apply recommended grease to the hole (a) of latch (6).
Fit the seat (1) as follows: insert the tabs (b) (on the front side) under
the rubber pads (c) of the gloves compartment;
then push the seat rear side until hearing the lock latch click.
...
Filling the clutch circuit
Warning
Clutch fluid will damage painted surfaces if spilled on them. It is
also very harmful if it comes into contact with the skin or
with the eyes; in the case of accidental contact, wash the affected area
thoroughly with plenty of running water.
Remove cover (1) and membrane from the clut ...