It is written on the VIN plate and in the owner's handbook, under
specifications.
You have Kerb weight and Gross Vehicle weight. Take the former from the
latter and you have the max payload.

Don't know about the weight but there's not room for much anyway.  If you
fold the back seats down you don't get a flat floor and you can't get the
driver's seat right back.  And the rear seat backs are split wrong for a
right hand drive car.  Something tells me that they don't really intend this
as a serious load carrying car and I am sure my golden retriever would agree
with me if he saw the space he would have to sit in :-(

Ron Robinson