Short Answer Overpaying for an apartment that violates local rent control caps will drain your savings indefinitely unless you file an official statutory complaint against the landlord. Since the 2020 reform, the timing decides everything: send your formal objection ("Rüge") within thirty months of the contract start and you can claw back every overpaid euro retroactively to day one — miss that window and you only recover from the objection onward. What Most Expats Don't Realize You signed an inflated lease for a plain apartment because you were desperate to secure shelter and assumed the price was legally verified. You discovered much later that your landlord was charging far above the maximum allowed by the local "Mietspiegel" (rent index) — but by then the thirty-month window had quietly closed. Your objection still capped the rent going forward, yet the €3,600 you had already overpaid since move-in stayed permanently in the landlord's pocket. What To Do * Open your city's official online "Mietspiegel" calculator tool and input your apartment's exact square footage and building year. * Check the three exemptions before firing your objection — new construction first used after October 2014, comprehensively modernized units, and a previous tenant who already paid the same rent — ideally with the local Mieterverein. * "Ich rüge hiermit die Überschreitung der zulässigen Miete." (I hereby object to the exceeding of the permissible rent limit.) — send this precise legal phrasing via registered mail; within the first thirty months it unlocks full retroactive recovery. The Truth Germany's rent control mechanisms do not apply themselves automatically to active residential leases. The system relies entirely on the tenant triggering the formal process, and it rewards speed: the same one-page objection recovers years of overpayment when sent early — and almost nothing when sent late.