Indeed, this balcony stands out against the background of the main building. This creates an unusual feeling. It seems that this balcony is "strange" in the background of everything else. Apparently this is a "manual" work of apartment tenants. People strongly wanted a balcony and they syroili. Although I do not think that they wanted their balcony to stand out. Nevertheless it looks beautiful and attracts attention.
On the general background of the photo, the balcony occupies a central place. All attention is focused on him. If you do not focus attention, it seems that this is a black spot that grows in the middle of the composition. I think that the key role is played by the color palette of various shades that surround the balcony.
It turned out an interesting and reasonable picture! Thank you!