The search term "Übergabe" is low efficiency and I can't think of a more suitable one at the moment, but your topic is definitely an FAQ, meaning there is a thread about it several times a year.
What would you agree on in the purchase contract? Nothing at all? And if the sellers then don't move out, you have nothing in hand and first have to file an eviction lawsuit and claim damages. Better to establish clear conditions from the start.
You may be right. Nevertheless, I think a handover "in one year" does not need an extension.
a handover "in one year" does not require an extension.
Then delete the extension and directly issue the contract as an enforceable copy = eviction order. But this is unusual and formulated very harshly - with almost every legal transaction there is first a warning or sanction before enforcement. At least I consider it fair with a grace period and penalty payment.
Thank you for your answers. We will then have a usage fee charged if the house is handed over to us after the agreed date. The reason for the late handover is that the owners are building again. We have received the checklist for the notary from the owners and sent it back. For us, this is the first real estate purchase, so it's all completely new territory for us.