This is where I stayed:
https://www.airbnb.com/rooms/15679230
The area isn't that nice, and generally speaking, Paris is VERY different not only from district to district but also from block to block.
Say, you go down South 2 blocks and you enter another world.
I lived in USA and travelled to many countries, I come from ex USSR so I can talk to different people easily, I honestly believe if you are not acting as an asshole you would do well almost anywhere.
The apartment has it's Parisian charm - basically speaking it's old and not very well kept according to even my standards, but it's fairly cheap.
Also, the cancellation policy is easy and they take no deposit as many do.
It's a 7th floor, the elevator goes up to the 6th, then you take stairs.
Very small elevator, 225kg max, usually 2 people only.