These steps were extracted from a longer article. The Mietshäuser Syndikat International and Prüfungsverbände der Sozial- und Wirtschaftsgenossenschaften e.V. were contacted on 2016-08-24 by Douglas Webb to confirm the steps are accurate and whether there are any important omissions.
The Prüfungsverband normally takes money. Initially registering costs about 800-2000 Euros. Additionally, your Genossenschaft needs to be a member in one of those Prüfungsverband and they check you every 1-2 years. This costs additional 400-800 Euros. It is unclear for now if we could get this membership for free.
Gesetz betreffend die Erwerbs- und Wirtschaftsgenossenschaften (Genossenschaftsgesetz - GenG) - German Co-operative law
§ 6 Mindestinhalt der Satzung - Minimum requirements for a Genossenschaft Satzung
Gesetz betreffend die Gesellschaften mit beschränkter Haftung (GmbHG) - German LLC law
[Co-operative and Community Benefit Societies Act 2014 - UK Co-operative law, reference for English speakers]
[Model fully mutual primary housing co-operative rules - Put forward by Cooperatives UK and the Confederation of Co-operative Housing, reference for English speakers]