In this case, you might be classified as at-risk. If you haven't been contacted already, you should contact your nearest public health office (“Gesundheitsamt”) and consider self-isolating for the next 14 days.
Please don't hesitate to inform homefully about this case, regardless of whether you or a flatmate is infected. We want to make sure that no new flatmates are moving into your flat, until the self-isolation and risk of infection is over. Contact us via "Submit a request" in the top right corner or check out here, how to contact Support.
Due to the risk of spreading the infection to healthy members of our Community, we cannot allow you to transfer to another shared homefully flat.