1. You need to leave enough time for the day. You can enter from10pm to 1pm, and then stroll around until around 6pm in the afternoon.2. To take a bus in the city, you need to take the subway first and then take a bus (or take a taxi, but there are not many buses available) - it takes over an hour. (You can easily swipe the purchased bus or subway weekly card.)3. Simple security check, easier to recognize than the Louvre, follow people.