Double KfW funding for a granny flat

Hello everyone,
we are planning to build soon and are considering building a granny flat attached to the house, which would initially be used as an office and in a few years the parents could move in there. Now the question arises whether we would receive double the KfW funding even if the granny flat is not used as such immediately after construction completion. Does one have to prove to KfW that the granny flat is actually being used (for example, a rental contract), or are the construction plans sufficient?

Thank you very much in advance

yes. that's enough for them. then it's just subsidy fraud, as to whether they consult with the tax office during the process to check if income from renting is earned, I can't tell you.

we received the funding without proof of renting.

if everything is done properly, you don't notice a landlord. then you can deduct tons of stuff... and for that reason we actually did rent it out. it's simply worth it.