Searching for a flat from the beginning of February to mid-July

I am an Italian PhD student in Mathematics in visit at the University of Tübingen in the first semester of 2018.
I am a tidy person that loves cleanliness.
This is not the first time I am in an apartment for rent and the previous hosts have recognized me as an excellent guest.
I am going to move to Tübingen to continue my research for my PhD thesis because one of colleagues coworkers of mine is moving too, and also to interact with the other researchers present in the University.
I would like to learn a bit of German in my period of staying and also improve my English because of the presence of a lot of international students to interact with.
Furthermore I really like visiting new places, so I consider that as an opportunity to travel in the other cities of Germany.
Other interests that I have concern doing sports, international politics, and watching TV.