The US has a similar stature, the Paperwork Reduction Act, a "law governing how federal agencies collect information from the American public", with the aim being to "not overwhelm [the public] with unnecessary or duplicative requests for information" and that the data collected be "a good fit for its proposed use" and further still "To respect privacy, we avoid asking for personal information that’s not relevant or necessary." https://pra.digital.gov/about/
In practice, of course, this is all bullshit and any data that the government cares to collect is rationalized as fitting all those requirements.
So I'm curious if the German Datensprsamkeit is actually effective?