In the Zusatzblatt of my Blue Card, it is written:
Beschäftigung nicht gestattet mit Ausnahme der Tätigkeit als Software Engineer bei ABC GmbH, Ort
Selbstständige Tätigkeit gestattet
Nach 2Jähr. Versicherungspfl. Beschäftig. ist Beschäftig. jeder Art gestattet
Now, there is a chance to help out on a university research project as Wissenschaftliche Hilfskraft in my spare time, e.g. 40 hours per month.
However, to do that, apparently the university would want me to sign a HiWi contract, as usual.
My understanding is that, I can only work as a freelancer (Freiberufler), but not as an employee of any other organization. Therefore, I'd need to invoice the university for the services that I perform, instead of being able to sign a normal HiWi contract. I'll also need to register myself at the Finanzamt and get a separate Steuernummer.
Is my understanding correct?
The situation is annoying, since universities here are quite rigid, and it's quite possible that the department wouldn't be able to establish a freelancing working relationship with me due to all the bureaucracy, meaning that I'd miss out on this chance.