[testfoobar]

My understanding is that he is proposing a 4 year freeze on about 1 million units.

https://www.curbed.com/article/zohran-mamdani-housing-rent-f... archive: https://archive.ph/hnK4Q

"The 34-year-old democratic socialist’s pledge for a four-year pause on any increases on the city’s 1 million or so stabilized units, effectively giving a reprieve to about 2 million stabilized tenants, was at the center of his campaign"

I'm not directly familiar with Berlin. But this story about shortages is the expected outcome:

https://www.reuters.com/markets/europe/germany-must-build-32...

BERLIN, March 20 (Reuters) - Germany, lagging in its building goals to alleviate a housing shortage, needs to construct 320,000 new apartments each year by 2030, a study on Thursday showed.

[JumpCrisscross]

> 34-year-old democratic socialist’s pledge for a four-year pause on any increases on the city’s 1 million or so stabilized units

Out of 3.7mm [1].

> not directly familiar with Berlin

Not comparable. Berlin froze rents “on more than 1.5 million” apartments in 2020 [2] out of about 2mm. 25% versus 75%.

Also, Berlin’s politicians didn’t propose a construction agenda. Mamdani has. (“New York City voters on Tuesday delivered a strong message in support of building more housing, passing three proposals that pitted City Hall against the City Council in an effort to rewrite decades-old development rules” [4].)

[1] https://www.nyc.gov/content/tenantprotection/pages/fast-fact...

[2] https://www.nytimes.com/2020/01/31/world/europe/berlin-gentr...

[3] https://www.berlin.de/en/news/8283996-5559700-housing-stock-...

[4] https://www.nytimes.com/2025/11/04/nyregion/nyc-ballot-measu...

[testfoobar]

Increasing supply brings down prices. But a builder will not build at a loss or an imminent threat to their rental income from expansion of rent freezes.

A city with an expanding rent-freeze is not inviting new supply.

[mejutoco]

Berlin reverted the rent freeze later because it was deemed unconstitutional. Many people had to pay back the money they "saved". Without entering in the other discussion the Berlin case was not a success.