Review of Conny, the rent reduction service

Berlin has rent control laws. If your rent is too high, you can get it reduced. Conny helps people reduce their rents. You only pay them if it works.

Visit Conny’s website

In this guide, I explain how Conny works, why I think it’s too expensive, and other ways to lower your rent.

How does Conny work?

This is how the rent reduction process goes:

  1. Calculate your rent reduction
    Use their rent reduction calculator, answer a few questions, and upload a copy of your lease. This takes around 10 minutes, and it’s in English. Then they tell you how much they can lower your rent. Their calculation is often optimistic.1 Your real rent reduction might be lower.
  2. Send the required documents
    Conny will email you. They will ask for a signed Vollmacht, and a copy of your lease. They need the Vollmacht to represent you.
  3. Wait
    If your case is accepted, you must wait. Some cases take a few days. Other cases take a few months.
  4. Get results
    If the case is successful, you get the refund in your bank account. If the case is not successful, you get a message that explains why. You only pay Conny if they are successful.

My review of Conny

It’s expensive

Conny charges 6 months of rent reduction, plus VAT.14 You only pay if they lower your rent.

Example fee

Old rent: 1000€ per month
New rent: 900€ per month
Rent reduction: 100€ per month

Conny’s fee: 100€ × 6 months + 19% VAT = 714

When you lower your rent, you get money back for all the months that you paid too much rent. If you lived in this apartment for 3 years, you might get 3 years of extra payments back. Conny keeps that money too.

Example fee

Old rent: 1000€ per month
New rent: 900€ per month
Rent reduction: 100€ per month
Time in this apartment: 18 months
Total rent reduction: 100€ × 18 months = 1800

Conny’s fee: 100€ × 6 months + 1800€ + 19% VAT = 2856

In my opinion, this is too expensive. There are cheaper ways to lower your rent.

I like that you know the cost in advance. If you hire a lawyer instead, you must pay them by the hour. If they can’t lower your rent, you still need to pay them. Conny has clearer pricing, but it might be more expensive in the end.

It can take a long time

It can take a few months to lower your rent. This is not Conny’s fault; German courts are slow.3 It would also be slow if you hired a lawyer or joined a Mieterverein.

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 negative reviews mention the long wait times and the lack of communication.2 As Conny wins more court cases, many landlords choose to cooperate, instead of going to court. Those cases get resolved faster.

It makes landlords angry

If you lower your rent, it can make your landlord angry. Your apartment is their investment, and you make them lose money. They can try to kick you out, or stop answering your calls.5

This is illegal. They can’t kick you out or stop doing their job because you lowered your rent.4

Your landlord can take revenge in other ways. For example, one user lost their garage space and their garden access.6 Another user says their landlord stopped answering their calls.7 Some landlords try to use Eigenbedarf to kick you out.

Your landlord can also find legal reasons to end your lease.8 For example, if you sublet your apartment without permission,9 or keep a pet without permission, your landlord might try to kick you out.

You have to decide what is more important for you: the money you save, or your relationship with your landlord.

It works

The most important part: their service works. Conny is good at lowering your rent. One of my friends saved 324€ per month with Conny. There are many more success stories online.

But Conny is not the only option. There are other ways to reduce your rent, and some might be cheaper.


Conny does what it says. They lower your rent for a fee. Conny might be much more expensive than other options, so you should look at those options too.

The good parts:

  • They take care of everything
  • You only pay if it works
  • You know the costs in advance
  • It works

The bad parts:

  • The fee is really high; there are cheaper options
  • It can take a long time
  • They are hard to contact
  • It can make your landlord angry

My recommendation is to try Conny’s rent reduction calculator.

In general, I think using Conny is a good idea. If you can save hundreds or even thousands of euros, it’s worth the trouble. However, I would try joining a Mieterverein instead. Visit their website, get a quote, and decide if it’s worth it for you.

Conny alternatives

  • 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 tenancy lawyer (Mietrecht) to lower your rent. You will get much better customer service, but it will cost you more, even if you don’t get any rent reduction. If you have legal insurance, it might pay for your lawyer.

English-speaking lawyers in Berlin

Where to ask apartment questions

Sources and footnotes
  1. Trustpilot, 

  2. Trustpilot (2024), Trustpilot 

  3., Trustpilot 


  5. Reddit (2023), Reddit (2024), Reddit (2023) 





  10. Trustpilot, 

  11., Trustpilot, Trustpilot, Trustpilot 

  12. Trustpilot, Trustpilot, Trustpilot 


  14. Conny (June 2024)