Berlin has rent control laws. Overpriced rent is one of the most common housing scams. If your rent is too high, you can get it reduced. Conny is a service that helps people reduce their rent.
In this guide, I explain why I don’t recommend Conny, and list better ways to lower your rent.
High fees
Rent reductions are retroactive.22 If your rent was too high, your landlord must refund all the extra rent that you have paid. For example, if your rent was €200 too high for the last 2 years, you would get €4,800 back.
Conny keeps that refund.20 If you paid too much rent for a long time, it’s usually cheaper to hire a lawyer. The Berlin court judged their fee excessive.10
Many reviews complain about Conny’s obscure, confusing pricing, especially when you cancel their service.15 It’s really hard to find clear pricing information on their website.
On the bright side, you only pay if they win or if you cancel their services. If they can’t reduce your rent, you don’t pay anything. This is safer than hiring a lawyer, because lawyers usually charge by the hour.
Shady business practices
There are many stories of people who were surprised that they were stuck in a contract with Conny, and that they could not cancel without a really high fee.18 They were sued because of it.11
Others were surprised that Conny acted so fast, seemingly without their consent.19
Their rent reduction calculation is optimistic. There are more realistic rent reduction calculators you can use.1
Deleted reviews
Conny gets negative reviews removed from Google Maps. They got over 100 reviews removed in the last 12 months.12 This means that you can’t trust online reviews. You can still find many real reviews of Conny on Reddit, and they are very negative.
Conny also has an affiliate program. Websites that promote Conny make money when they convince you to use their service. These sponsored articles are rarely neutral.
This is normal for German businesses.10 It does not mean that the business is bad, but it means that you can’t trust reviews and articles about them.
Angry landlords
If you lower your rent, it can make your landlord angry. Your apartment is their investment. If you make them lose money, they can become very unpleasant.5 This is not Conny’s fault, but it can happen.
Your landlord can punish you for lowering your rent. For example, you might lose your garage space or your garden access.6 Your landlord might stop answering your calls.7 They might try to use Eigenbedarf to kick you out.16 It’s illegal, but it happens.4
Your landlord can also find legal reasons to end your lease.8 For example, if you sublet your apartment without permission, or keep a pet without permission, your landlord might try to kick you out.9
This is more likely to happen with private landlords. For many commercial landlords, it’s just business.21
Wait times
Cases can take months or years to process. This is not Conny’s fault; German courts are slow.3 Other ways to reduce your rent are also slow. As Conny wins more court cases, many landlords choose to cooperate instead of going to court. Those cases get resolved faster.
Some cases are processed in a week, and others in a year. Even if it takes a long time, the refund is retroactive, so the refund amount is the same.
While you wait, you don’t get many updates. Many reviews mention the long wait times and the lack of communication.2
But it works
Still, Conny’s rent reduction service works. They will successfully lower your rent, and you might save hundreds of euros per month. Some of my friends used their service and save a lot of money every month.
Conclusion
Per my content policy, you get the same advice as my best friend. I tell my friends to avoid Conny.
Their service works, but their fee is too high, and their business practices are not great. Many reviews complain about the confusing fee structure and the shady business practices.14
Visit their website, get a quote, look at the other options, and decide if it’s worth it for you.
Other ways to lower your rent
Use these services to check if your rent is too high:
- Mietencheck.de
A free online calculator. It shows you if your rent is above the Mietpreisbremse limit. It’s in English. It’s made by a non-profit association. They don’t sell anything. - Rent review office (Mietpreisprüfstelle)
Official service by the city of Berlin. You must book an in-person appointment. - Tenants’ association (Mieterverein)
If you are a member, they can check your lease and tell you if your rent is too high.
Use these services to lower your rent:
- Tenants’ association (Mieterverein)
Pay a monthly or yearly fee, and get help when you need it. They can check your lease, check your Nebenkostenabrechnung and help you reduce your rent. They are cheaper than a lawyer, and offer more services than Conny. After you join a Mieterverein, you must wait a few months before you use their legal services.13 - Tenancy lawyer (Anwalt für Mietrecht)
Hire a lawyer to lower your rent. It costs a few thousand euros.23 Your legal insurance might pay for it. - Conny alternatives
Where to ask apartment questions
Sources and footnotes
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Trustpilot (2024), Trustpilot ⤴
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goo.gl, Trustpilot, Reddit (2025) ⤴
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test.de (2025), Reddit (2023), Reddit (2024), Reddit (2023) ⤴
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mueller-radack.com (2026) ⤴
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beck-aktuell.de (2024), eulawanalysis.blogspot.com (2024) ⤴
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Many of the reviews I cited before got removed. Google Maps (August 2026), Reddit (2025) ⤴
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Trustpilot (August 2026) ⤴
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Reddit (2025), Reddit (2026), Reddit (2025), Reddit (2025), Reddit (2026), Reddit (2026), Reddit (2025), Reddit (2025) ⤴
