Non-compliance with the development plan by the neighbor

How am I supposed to conjure up a 3-meter hedge in 1.5 years? Besides, it's nice that he builds such nonsense on the border and expects me to figure out how to protect myself?

You can just buy big plants right away. At pflanzmich.de you can choose the size. Besides, the neighbor could just sit on the lawn at that spot. And then? That's his land, not yours! You are responsible for your property and if it is too exposed for you, then you have to build protection yourself. Not the neighbor.

After the latest update of Google Images, our city has become active in many places and has initiated the removal of unauthorized structures. In other areas, drones are already being used. This information might be valuable for your neighbor...

Yes, I believe the district updates the aerial images here every 3 years.

I mean, I would also like to build a garden shed.... the neighbor actually wanted to too.... and no terrace. I wouldn't have cared either. He says he might want to add one on.

I just have concerns that in 2020 the building authority suddenly knocks..... when they have new images and I might have to remove my shed.

What kind of building authorities do you all have? Here, they are so busy with everything else that they don’t care at all about such trifles. And even if they do, they tend to try to legalize illegal constructions afterward rather than enforce a dismantling. By pure coincidence, I know that in the last 10 years there were exactly 2 cases where dismantling had to take place. And those were houses. And we live in a big city.

It is often a matter of the temperament of the heads of office. Some feel personally attacked and react accordingly "without humor".

I know it more like this: if someone goes overboard with their hacienda in the outdoor area, the office, which otherwise does not suffer from a lack of work, has to take action. Only if the person involved then has a shooting club brother with a Schwibbschwager in the city council, the whole thing escalates and is expanded "on principle" to a land measure. Collusion always works (only) as long as some small faction thinks they are not getting enough crumbs from the cake. Then there is yelling and snitching to the superior authority.

But to the OP - I don’t quite understand two things:

His actual terrace is on the other side of the property

So why is he building a stage on your border – are you married to a MILF whose sunbathing could delight him?

And: where is your privacy screen problem? – if he does not get moving with his promised fence, then just put up a temporary privacy screen that is visually suboptimal enough on his side to motivate him to speed up. It doesn’t have to be something that needs to grow first – for all I care, bean poles with camouflage netting in between.

By the way, I find the suggestions for de-escalation worth considering: think of chain-link fence vs. pea shrub – in the end, both parties were the laughingstock of the nation on Stefan Raab, and even today – long after Lisa Loch – remembered.