German Rental Contract error. Can landlord back charge 18months?

Question

Berlin Landlord made an error in the contract, and now wants all tenants to correct the error by paying sum's going back 18months. Can they?

A little more detail:

• A friend moved into a new apartment in Berlin 18months ago.
• Last week, they received a demand, to be paid within 15days, with back dated charges for all 18months.
• The contract he (and other tenants have) references the size of the apartment in sq meters, it references the total monthly rent to be paid, but does not reference a formula on how the total monthly rent was calculated.
• The reason for the demand is the landlord discovered they calculated using the wrong sqm cost.
• I believe the landlord might be able to increase rent going forward, but not back date 18months. True/false?

Thanks

Answer 1

When a contract states a thing that you get for a stated price, that means you should get the thing described, and you pay the stated price. If the landlord makes a mistake and wishes he had charged more, he can wait until the end of the lease period and then increase the price as he desires. He cannot raise the price until the end of the contract, and cannot retroactively charge that increase. (It's impossible to imagine there being contract language that allows that outcome, but we will assume there is no such clause).

If the stated area is not as stated, especially if the area is actually smaller, the landlord is in breach of the contract, and could be sued for damages. It would depends on how different the areas are, when it comes to assigning damages. For example, 4 sqm in a unit with 800 sqm is not likely to result in any loss to the tenant. If the unit is bigger than stated, the prospects for damages are even less, perhaps a bit for added heating cost. Either way, if the size is incorrectly described, that is the landlord's fault, though probably not worth bothering with a lawsuit.