Jean's place is very authentic, and perfect for a short trip to Paris! As others have mentioned, it's a diverse area of Paris, but we felt safe the whole time we were there. It's incredibly easy to get to Gare du Nord (only a 15 minute walk, shorter by Metro) and easy to get to wherever you want to go in Paris.
There isn't really a comfy sofa so to speak, so if you're planning a longer trip this might not be for you, but the bath in the bedroom was a great touch. Eggs and coffee were left for us by Jean which was a thoughtful touch!