I had a 90 days Schengen visa, but unluckily I lost my passport along with my Schengen visa in Berlin a month ago. I've been staying in Germany for the whole month. Now I've obtained a new passport from my own country's consulate. Can I use this new passport + police report + photo copy of my lost Schengen visa to go outside Germany and visit other Schengen countries? I didn't find any exact regulations for that, so can anyone help me out?
Within the Schengen Area, there are no border checks between countries. This is actually by law; a Schengen country can't introduce systematic passport checks at the border with another Schengen country even if they wanted to.
So you should have no trouble moving around within the Schengen area. If you choose to leave the Schengen area of course, you would likely need a new visa to get back in (the documentation you have might work to get you back in, but I wouldn't count on it). If an official such as a police officer asks you for your papers, then the documentation you have should be fine.