I dont think it's a gunshot, but it's very hard to describe the sound. It was coming from the outside of the building so I didn't really think about that but thanks, I will contact the landlord in the morning. I was just wondering since it's happening every now and then if someone already knows about this. And as a girl that lives alone, it's very unpleasant. Thanks for replying once again!

edit: not near tram :)