Acquire green land adjoining the property?

Or a playground for those in need of protection :D

Dog meadow.

Honestly: I would buy it. If you're unlucky, you would end up taking care of it anyway, even though it belongs to the city, so it doesn't become an eyesore.

How about a lease agreement with a purchase option after 10 years?

When negotiating the price, keep the following in mind: to whom else is the city supposed to sell it? Nobody except you is going to buy it, there are no other potential buyers.

Presumably, they will have offered you the piece at the regular building land price. I would comfortably push that down to the garden land price, i.e., offer €5/m². The clerk will probably burst into tears, but they'll have to get through that. :)

In the end, you won't get it for that price either, but this way you let them see that you’re not stupid. The city isn’t offering it just for fun; they have a lot of work with it because they have to maintain it annually, so feel free to start very low and wait to see what happens. I would then set a personal deadline and consistently decline the city’s offer if it gets exceeded.

Best regards
Dirk Grafe

Here one can also seriously ask the question of who did the planning back then. If the part had been divided accordingly at that time, the area would have been sold at the usual sqm price for building land. Unless there were other plans such as parking spaces or containers.

But I would also gamble. Presumably, the community wants to call up a 5-digit amount here.

Thank you for the abundant feedback! It would probably indeed run into five figures, and we currently prefer to invest that in garden design. However, I really like the proposal with the lease agreement including a purchase option or directly a kind of rent-to-own (of course interest-free) over, for example, 20 years. For reasons of fairness towards other builders who accepted the price at the time, they do not really want to go down in price. Glass containers and playgrounds are actually available within 150-200m distance. I hope they don't need them twice in the residential area.

But briefly about the ongoing costs again. Property tax increases, street cleaning. What else??