I had extremely high hopes for this place. The pictures are accurate, the location is great, and communication with the host was good (initially). It really is a beautiful apartment, but looks can be deceiving.
I'll start with the MAJOR issue I had that resulted in me leaving after the first night. To start, I checked in with one of Alexandre's friends who was great, but I thought it was a bit odd that Alexandre was not there himself.
Anyway, about two hours after I checked in, I decided to take a shower. There are two bathrooms in the apartment, but I went with the bigger one. I turned the water on and the bathroom floor immediately flooded, from what I think was poor shower drainage and an overall poor design. There is no door or bottom rim to the shower, so water literally just starts pouring out. After cleaning up all the water (with the only other towel that was provided to me), I decided to take my chances with the other shower. The same exact thing happened. I even dug around in the shower drain to pull out a disgusting piece of clogged hair, but the water still flooded this second bathroom.
About 20 minutes later, I got a phone call from downstairs. It was a woman sounding very upset, saying she was the store owner of the place below, and that there was water running down her walls from the apartment and the store was flooding. I let her and another guy come up so they could check it out, and they had to shut off the water main in the apartment so the flooding would stop (they suspected a broken pipe). I frantically tried to get Alexandre on the phone, and he ended up speaking with the woman (in Spanish so I couldn't fully understand). When they got off the phone, the woman told me that the apartment manager is shady and he is telling her the leak is my fault (!!!). He said "it is not my problem, it is her problem." She also said something about renting out apartments that you don't own is illegal in Madrid (my guess is Alexandre rents it out for someone, and neither of them even live in the city). Alexandre later messaged me saying, "Don't tell Airbnb" so obviously something very shady is going on with him. He told me to wait until Monday (two days later) for someone to come inspect the pipes. Obviously, I was not going to stay somewhere with no running water and ruin the start of my vacation.
The next day I was able to contact Airbnb by phone, explained the situation to them, and they were able to refund me for the remaining week of my stay. I ended up finding a better apartment only 10 minutes away through Expedia.
Alexandre continued to message me, saying he didn't understand why I left, then that the woman was "inventing things," and that the leak was coming from a different apartment. I felt like he was trying to gaslight me, when obviously he wasn't even there to see what was going on.
Another word of warning about this apartment: the cleanliness is questionable, notably the linens. The (two) towels he left me smelled very strongly of detergent, however one also smelled like mildew. And check the bedding as well: I found hairs (definitely not mine) on the living room couch pillows and in the bed sheets. There is also a noticeable grease stain on the fabric headboard.
One more word of warning: the streets below are NOISY!!! The first night I was there, people were yelling and partying until 6am. I'm definitely glad I found the second place, which was much quieter (probably because it was further away from Gran Via).