We had a really lovely stay at the Snob - it was clean, the staff were friendly, the breakfast was tasty, the bed was extremely comfortable. The metro is so close to the hotel, you can be in Monmartre in about 25 minutes. The Notre Dame is about a 15 minute walk, as is the Louvre!
There are great restaurants around, it feels incredibly safe - the staff are all very friendly too and are very knowledgeable, they even stored our suitcase once we’d checked out as we had a late flight.