We rent out one small private room in our beautiful and luminous 70qm apartment in Barcelona. The room has one double bed and a small balcony, it's perfect for either one person or a couple. Sant Antoni is a centric and very lively neighborhood and offers everything from great restaurants and bars, shops, a market and very good public transport.
It might get a bit noisy on weekends but only until 00.00 or 01.00. We have a cat so be aware if you're allergic.