@Till-and-Jutta0 The $100 cleaning fee the host was charging this guest is not just for the toilet -- it is the cleaning fee that is charged by the host to clean the entire property (wash linens, floors, dust, vacuum, remove trash, clean bathrooms and toilets). A guest should receive a sanitary property as paid for by the cleaning fee charged to the previous guest, and IMO, this guest is being charged for cleaning the property after their visit.
If the guest arrived to a dirty bathroom and kitchen, the host should be sending the cleaners back or providing a refund of some amount from their nightly rate -- and then having a chat with the cleaner as to the oversight. Is the host not leaving enough time between rentals for the cleaner to get there and do a proper job?
To the guest @Javier1666 , from the AirBnB website:
We recommend discussing any refund amounts with your Host through your Airbnb message thread before submitting a request in the Resolution Center. However, if you and your Host aren’t able to come to an agreement, you'll have the option to ask Airbnb for help finding a solution. Issues must be reported to Airbnb with 72 hours of discovery to be eligible under our Rebooking and Refund Policy.