Seems like honeycombs / interior courtyards provide a pretty decent solution to the viewing rights problem, at least to the 4-6 floor range (e.g. Berlin, Paris)

Seems like honeycombs / interior courtyards provide a pretty decent solution to the viewing rights problem, at least to the 4-6 floor range (e.g. Berlin, Paris). If the buildings are aesthetically pleasing and appropriately spaced, the limit comes down to sunlight.