Regulation on the slope and height of retaining walls

Hello everyone,
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In order to create a level surface (garden), part of our sloped plot is to be filled with soil and supported on the downhill side with planting stones (stepped arrangement) (Picture 1).



A terrain height difference of approximately 3.5m must be compensated overall.
Is there a regulation (development plan, state building code, DIN, etc.) specifying up to which slope and up to which height the planting stones may be built without having to install safety measures against falling (e.g. fence)?
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Possibly, an arrangement of several small retaining walls placed one behind the other could be the better solution (Picture 2). But even here, we do not know how large the distance (width) between two "slope reinforcements" must be.

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Thank you in advance.

That can vary regionally, for example with us walls in front of the house 1m high, behind the house 1.8m. At the intersection area even max 0.7m. But you have to study your development plan. From 1m height you also have to make a fall protection towards traffic areas. With us the law is handled leniently as within a property there can be a height difference of 3-4m in places.

There are probably no regulations regarding the angle of inclination (except those from the stone manufacturer) - but there are regarding the respective height to the boundary distance. You can find this in the municipal building regulations.

... this is neither about static specifications from the stone manufacturer nor about distances to public paths or intersections. The entire project takes place exclusively on private property, behind the house. Unfortunately, the development plan provides no information at this point.

The regulations known to us define the fall height as the vertical height difference between the standing surface and the adjacent lower, sufficiently large and load-bearing surface. Structural measures are required here starting from a fall height of 1m.

In our case, however, the construction is to be carried out with a "slope," and the specification "sufficiently large" surface is not so helpful.

The regulations known to us define the fall height as the vertical height difference between the standing surface and the adjacent lower lying, sufficiently large and load-bearing surface. Structural measures are required here from a fall height of 1m. In our case, however, the structure is to be built with a "slope", and the term "sufficiently large" surface is not very helpful.

I see the height as the distance between the top and bottom of the wall, and a slope or step does not change that. I would also assume 1m as the "depth" of a step before another height increment is allowed. For shorter intervals between height increments, I would consider the entire structure as only ONE and add the step heights accordingly. Before it becomes a space-consuming structure, better put a railing on top. However, keep in mind that it will be a structure one way or another – with all the consequences for permit requirements and setback distances. And furthermore, keep in mind that earth masses can also slide. A slope always remains a slope and means renouncing flat surfaces, no matter how many crocodile tears are shed about it. Some slopes can hardly be reconciled with (justified) regulations other than by partially accepting them. That many areas considered as building ground today were scorned forever before has its reasons. It is not the task of land to be buildable everywhere – certainly not with terraces or houses without basements.

There are probably no regulations regarding the angle of inclination

Oh yes there are. I often read: slope angle less than or equal to 30 degrees. just ask the building authority. But basically, you can build on your property within the permitted areas as you like. You can also build yourself a 6-meter high climbing wall there, with or without an angle, if it is far enough from the boundary.