Visa Questions (Berlin)

Hi Internations,

I have several things going on in my life that I'm hoping that will be able to lead to me having gainful employment in order to get a visa:

First, I'm co-founding a nonprofit here in Berlin, and I have some questions about a self employed visa... Does anyone know if I would be allowed to hold another job while on a self employment visa? And has anyone who has been through the process have any tips?

Second, I met a really wonderful family here on Internations, and they need someone to clean, do office work, etc. for them. They're willing to hire me as an employee. I assume that such a job would fall under a general employment visa, but I'm not sure... If so, does anyone know if I would be able to get a second job in addition to the cleaning job? Does anyone have any experience with jobs like this?

If anyone has any information on this, I would really appreciate sharing, or if someone knows an agency that has information, that would also be really helpful.

Thanks!