Reader question: Does unconditional payment despite a known defect in the flat automatically preclude a reclaim of overpaid rent?
You reported a defect that arose during the tenancy but continued to pay the full German flat rent. Later a reduction for a retrospective period is examined. The landlord responds that you knew the defect and nevertheless paid unconditionally. Therefore any reclaim is excluded.
This conclusion must not be drawn automatically. In addition to the right to reduce the rent and a possible reclaim under § 812, § 814 BGB in particular must be examined. It links to the knowledge of not being obliged to perform. [BGB536][BGB812][BGB814]
First clarify the possible primary claim
Was a reduced rent actually due in the period in question? Which defect existed when, how was it reported and which payments were made? § 536c contains notification obligations and the consequences of their omission. [BGB536c] Without this examination the presumed overpayment would already be unsecured.
Therefore assign each affected month with documentation. A later repair alone does not prove the amount by which the earlier rent was reduced. The article neither sets a reclaim amount nor a specific defect percentage.
What you knew at the time is the next question
In the interlocutory decision VIII ZR 100/18 the BGH differentiated between knowledge of the facts and knowledge of the absence of an obligation to pay. For § 814 it is not sufficient merely to know the condition of the flat; the corresponding legal conclusion must be added. The recipient bears the burden of presentation and proof for the exclusion requirements. [BGH10018]
That does not mean only legal professionals can have the required knowledge. The decision in particular does not demand penny‑accurate or comprehensive knowledge of all elements of a reduction calculation. A merely approximate determination of a percentage does not necessarily exclude positive knowledge. [BGH10018]
What past communications play for
In the case at hand communications, in the trial court's assessment, resulted in a mistake: the tenants assumed a reduction required the landlord’s consent. This assessment contributed to denying positive knowledge of non‑liability. [BGH10018]
This is not an instruction to subsequently assert such a mistake. Instead preserve the correspondence that actually existed unchanged. Earlier enquiries, replies and advisory documents can help reconstruct the state of knowledge at the time. A later invented statement does not make the documents more appropriate.
Hypothetical case with two different periods
A tenant reports an impairment in spring and initially continues to pay in full. They consider landlord consent necessary for a reduction. In summer they receive concrete legal advice and thereafter continue to pay certain amounts. All events are fictional.
For a reclaim examination the months are not taken together into a single payment without scrutiny. The advice looks at the primary claim, the knowledge at the time and the declaration situation for each period. The earlier mistake does not automatically confirm later ignorance; conversely the later advice does not retroactively prove the same state of knowledge in spring.
Reserve and later set‑off clarify separately
A timely clarified payment declaration can be significant for future payments. It is not backdated to transfers already made unconditionally. The reservation possible upon acceptance of the flat under § 536b is moreover a different question from the knowledge exclusion examined here for later payments.
Finally have clarified whether and how an established reclaim claim should be asserted. Its set‑off against the next rent has its own prerequisites and is not settled merely by a private balance list. Your reliable working status includes the possible overpayments and the truthfully documented course of knowledge at the time.