Distance from terrace to property boundary

Thanks for your assessment. It would be great if, of course, nothing further is the matter.

If you spread the soil, probably no edge will form at all. The height differences at your place are so small that I simply claim that you are overthinking it.

I also have to say that I kept thinking the whole time that our new development area has a very slight slope – about 20 cm over 30 meters (length of a plot)... The apparently necessary height compensation does not exist with us. The soil and the beds just work out. If there are 10 or 20 cm height differences between two plots, they are balanced out with planting of hedges and bushes. Simply piling up soil around a rose creates a difference on a bed that can be secured easily with found stones. Nothing in the bed is level. Lawn edging stones, for whoever wants them, do the rest. In short: I don’t see or understand your problem. Except, of course, if you somehow want to see problems.

The "problem" is simply that he wants to build a fence without knowing how the transition to my side will be -> currently it is the earth embankment. In the end, there will be a bigger step between the properties, the fence will stand, and everything will turn into a mess, in the truest sense of the word. If I extend my curb from the house border as edging for the terrace, it just seems lower to me. Not only to me, but also to other neighbors who ultimately know more about the matter than I do. Even the company that removes and disposes of the embankment believes that an edge will form. Of course, if everything resolves amicably, all the better...

In the end, there comes a bigger step between the properties,

the fence stands and everything becomes mush,

Sorry, either you or I have a knot in the head! What kind of step? Mush? Plants will adorn the fence ... no one cares about the soil there at the fence. Of course, if everyone insists on their grass blades up to the property line and then they compete in their height: yes, then there is a problem.

If I continue my border from the house edging further as edging for the terrace

Do you want to continue your terrace stones along the fence? For what purpose?

The picture already looks intense.

The neighbor should just level it so that the property boundary is a straight line, then install a lawn edging under the fence to ensure that he does not divert water to you. An increase of 20 cm is already enough. The height difference of your terraces is certainly more than 20 cm. A look at his plan helps to clarify this.

You each have 3 m to adjust the height. There doesn’t have to be a step.

I’m just wondering who comes up with the idea of placing the terraces opposite each other?

You shouldn’t work against each other. You want to get along for a longer time.

The "problem" is simply that he wants to build a fence without knowing how the transition to my side will be

But that is "your" fault.

In the end, it comes to a bigger step between the properties

Which you then create yourself because you model your piles of earth. And do yourself a favor and measure the actual height difference. Take the garden hose and use it as a water level if you want. My claim in #24 was not baseless: Descriptive geometry: Parallel lines intersect in a vanishing point. This lies at eye level. You see, the door handle of his patio door is somewhat higher than the handle of your front door. Exactly how much cannot be determined this way, of course, since we do not know at what height your door handle was installed nor his. But his finished floor edge is quite certainly not 50cm above yours. Or take the patio chairs. Did you take the photo standing? Then the cyan line would be at street height + eye level = 196.7 + 1.6 = 198.3; his patio at 198.3 - 1.2 = 197.1, so 5cm above natural ground level at the house. If he now stubbornly stretches his height up to the boundary and you yours – in the south view, where the boundary height was also not correctly interpolated, you can see that you have to slightly remove earth – he would have piled up 20cm and you removed 15cm. If it comes to that, I will nominate at least one of you for the golden idiot of the year at the heute-show. So again, since my numbers are also subject to some inaccuracies: First determine the exact height difference and then find a solution with the neighbor.