Tax Question in Los Angeles

I have been trying to get an answer from Booking.com but they don't seem to understand my question.  I want to know if I pay Los Angeles business tax on the before commission amount or the after commission amount I earn as a homesharing rental.  I don't think I should have to pay taxes on the 15% I have to give back to Booking.com as commission. But since they send the full amount and then you are expected to send the 15% commission back to Booking.com after you receive the full amount, it hits your bank account and is it considered my income?

Help.