Looking for accomodation

Hi! I am looking for accommodation for the time period of 6 months starting at the end of June 2019 and ending around January 2020. I will be working at the Helmholtz Institute, hence I would appreciate a place nearby (preferably biking distance). I will be working on an internship project. I am interested in a shared or single room, but having people around to share the time and dinners is always appreciated. In my spare time, I like to read, cook and stay active. I am willing to pay around 400 euro per month for my accommodation. Feel free to send me any other questions.