By the way, I spoke with the construction workers today about the nail battens and asked them to remove them due to the risk of injury. They do have a construction fence around their property, but the battens are just lying next to it on our side and are not secured to the fence. They said they would clear the items away by the day after tomorrow at the latest; they probably want to reuse them.
I have refrained from dealing with the pile of earth for now, partly because it is really (still) not that big, and partly because eliminating hazards is more important to me right now.
If I hadn’t caught anyone, I would have asked the municipality for clarification on this. In any case, from my point of view, they would probably only try by email to get the owner to encourage the construction workers to clear away/secure the items.
I hope this was the most pragmatic approach and will lead to success.
Thanks already for all your opinions on this. If anything happens (or not), I will report back.