We are very satisfied of our stay in Javier y Carolina Appartment. We landed late (around midnight), but Javier Welcome us anyway with warm. The appartment is perfectly clean, perfectly located right behind the Cathedral. Maybe a bit darker than expected on the photo, but there is no point in staying inside during the day (and there is a nice terrasse).
Javier helped us to see a flamenco show at last minute, and keep our lugagges until our flight after we left (flight was on the evening).

Don't hesitate. Sevilla is one of the most beautiful city I ve seen.