Plot found but too big - Seeking construction partner

It would be possible, but in this price range there are also other plots.

I am shown 12 plots in Eichhagen that look more or less similar. Some of them may be built on. I can imagine that one or the other is more attractive, since there is also an existing building on this Hammer plot. The more offers there are, the harder it is to find a "partner". Ultimately, you are not really looking for a building partner, but want to step into the role of the broker. I would make a purchase offer for the one and that's that. Why should you worry about the seller's thoughts and nice-to-haves? Either you get it or not. The other plot or its sale is the broker's task and should not be your concern.

Thank you very much for the answers.

So far, the answers have been nice too, now comes the shocking wake-up call:

It's about this plot: 155004789. It is parcel 351 on the map. We would need the partner for parcel 352. The plan, as @11ant has already guessed here, would be to build detached houses. [...] in this price range, there are also other plots.

Ouch. I have been looking for a little plot like 351 for a long time – unfortunately not right next to the garden fence to the capital, because from my point of view at the Middle Rhine it is extremely remote (seven hours’ drive without traffic). 352 is quite usable, but finding a fool for 351 will not be easy for you. What you can build on 351 is a small cottage the size of house number 25. Take some broomsticks and barrier tape, put the broomsticks next to the survey markers and see for yourself the mess, how tiny it is. Even the semi-detached houses 27/27a put their garages in front of the houses instead of struggling through the building rights to have the garages in the garden. Their house size is saved by the fact that the plots are sufficiently large. The one for 351 will be sized so that the plot ratio for 352 is sufficient for the existing building including shed, without demolition. For 351, I could at most imagine a small semi-detached house directly attached to a (larger) semi-detached house on 352. Or you keep the "entire plot" as offered and use 351 yourself as a weekend property right next door. For me, that would be a dream, such a forest lot for a dandelion trailer, right next to the civilized house – only in my case near the wrong capital. But for you it is more a shattered dream, at least in terms of the plan presented here, to get rid of Dreizweiundfünfzig again and take Dreieinundfünfzig as a building plot.

Floor area ratio distress could at least be partially remedied by adding the hammerhead to the front property and granting the corresponding floor area rights.

Floor area ratio distress could at least be partially remedied by adding the hammer handle to the front property and the corresponding GFL right.

Exactly, then I would see a small semi-detached house possible for 351 instead of a shack.

By the way, it's not that small (approx. 17*25m) 441 m² according to the cadastre. So depending on the caseworker, 75-80m² of floor space will fit.

What you can build on 351 is a cottage the size of house number 25

Nonsense!

By the way, it is not that small (approx. 17*25m) 441 m² according to the land register. So depending on the caseworker, 75-80m² of floor area fits on it.

That's exactly right. And since the 34 applies, fluctuations and approximations also apply. If a building authority is keen to renew the structure, it will also approve 110sqm of floor area. That makes about 0.25 floor area ratio. And then you still have a front yard, space for one to two cars, and a nice compact garden.