Looking an apartment - long term

I've been living + working in Berlin for 4-5 years already and need to move to another place before April 15th. Therefore, I'm looking for another place to live I can call "home".

I'm looking for a place that would have the following caracteristics:
- Okay with cats: I have a lovely/adorable cat and I can promise that he won't make any trouble, he'll be comfy sleeping on/in the bed and not make a scratch other than on his cat tree.
- A rent no more than 800€ warm: I work as marketing for an online company and my current salary cannot make me afford more.
- Not picky about location as long as transport isn't too far: I work around Voltastrasse/Gesundbrunnen and currently live in Charlottenburg, so I'm used to take transports so I'm ok with a place that can be a bit "far" as long as transports are reachable/available.

MORE PERSONAL INFO:
I'm a 27 years old French guy who moved to Berlin in 2013 and currently work for an online company. I'm a very quiet and friendly person who enjoys quiet evenings at home. I always pay my rents on time (every month as soon as I get my salary) and always make sure to check if landlord is okay before any big change (new big furniture, putting shelves on walls, etc.).

I'm looking forward to be in touch and be your tenant, feel free to contact me by email or by message here.

Thank you in advance. :)