With its narrow balcony and big windows, this modest aerie offered sweeping rooftop views of the bustling north slopes of Montmartre — a neighborhood full of cafes, food shops, bookstores and several Metro stops that provided easy access to the whole of Paris. It was a great place to sample Paris without tourists. The apartment also gave a taste of the capital’s intellectual life. It was great to be in a book-lined space filled with evocative photographs and objects from our host’s life of travel and exploration.