To do the check in in this flat the renting company requires you to pay a deposit (in our case it was even more expensive than the stay) + a tourist fee. We found it quite annoying as it is NOT stated in the price when you book the airbnb and it's just written as a small caveat in the listing description/house rules. They sent us some payment links (after we'd booked and payed with Airbnb without possibility of cancelation) requesting these extra things... We found it off putting and very inconvenient compared to other accommodations we've booked through airbnb. It's important to be very clear and upfront.
Apart from this the flat is well decorated and comfortable, perfect for a few days in Barcelona.