Freelancing in the EU from Germany? (Berlin)

Hello all, I'm wondering if any non-EU residents in Germany have any experience with freelancing for European clients. I have a residence permit and full unrestricted working permit for Germany, as my husband is German. I am a freelancer and have the opportunity to do work for a client in Norway. Does anybody know if this is legal and/or what the tax implications are? I have searched both German and Norwegian government websites for information but to no avail. Thanks in advance for any tips or resources!