Wanting to know the tax implications etc

Hi Frosty5239,

Welcome to Expat.com!

A new topic has been created as from your post on the Germany forum.

Best of luck,
Christine
Expat.com team

German tax law is very complicated, so you're well advised to visit a professional tax consultant (Steuerberater) instead of relying solely on an Internet forum.

In short: You are tax liable in Germany with your complete world income if you have a permanent abode in the country. This tax liability is independent from your visa status or how much time you actually stay there.
Thus, if you stay in a hotel or temporary accommodation during those 28 days in Germany and give it up when you're out - no tax implications. If you buy or rent a place that is also available to you when you're out - tax liability!

Germany-sourced income is taxable in any case.
Tax treaties with other countries might specify exclusions or deviations from the above.