We arrive in Beijing at 10:30pm in transit to Paris flying out the following day at 1:30pm. Do we need visa if we stay at hotel outside airport?

You need a transit visa if you stay at a hotel outside airport. If you are Australian, you can try to apply for 24-hour stay permit when you arrive at Beijing airport. Once you get it, you can go out of the airport. In this case, you don't need to get a transit visa in advance.