The flat is situated in the heart of Sofia, just around the corner of the famous 'theatre street'. The National Theatre itself is just across the street and you'll be surrounded by some of the best parks, cafes, bars and restaurants in the city.
Everything you would need in the city is within a short walk away. The street is central, but quiet with dozens of shops around. I would recommend the flat to couples, solo adventurers, business travelers, and families with kids.