Just wrote a little something about beauty:
Of course, it depends on what kind of wall is being put up. A finished garden wall, whether made of broken wall blocks like the Santuro wall, hollow chamber blocks, or a Friesenwall, is naturally also legally untouchable from a visual standpoint. Of course, the neighbor has the option to place something of their own on their side in front of it if they don't like how it looks. A pre-purchased privacy fence is also something different than a board fence nailed together from formwork boards that looks like a construction site privacy fence in the shopping street ;)
However, if you build a wall out of formwork stones (also known as basement wall stones), whose purpose and production are not intended as a decorative garden wall, but rather as a wall stone with a static function, or to retain terrain, or also used as a slurry channel and drive silo, then the neighbor can indeed take legal action to, for example, enforce plastering/painting of the wall so they don’t have to look at a shell construction. Similarly, when building a house, there is a deadline by which the shell construction must be externally completed (in France, for example, people often take a very long time with this because certain money (taxes) only has to be paid after the façade is completed ;)
