I am travelling to Paris on the 22nd of December. I was looking for a youth hostel close to Paris city centre. But the problem is that I will arrive in Paris at midnight. So, I am wondering whether I will get any hostel in Paris which will allow me to check in at midnight. Will public transport be available at that time?
UPDATE
I am planning to travel from Brussels by iDBUS, which will arrive at Paris-Bercy station, 48 bis Boulevard de Bercy, 76012 Paris.
Most hostels and hotels don't care what time you check-in, simply because they have staff manning the reception 24h. Nevertheless, it is good policy to warn them in advance if you plan on arriving late, to avoid them considering you as a no-show and cancelling your booking.
In your case, I would say that midnight is not really a late check-in per se. So I would not be worried. To be safe, email the hotel/hostel and ask.
You can check the departure times of public transport lines (RER, Metro, Bus, etc) on the RATP website here (sorry the page exists in French only, but google translate is your friend). Timetables vary between weekdays (Monday - Thursday), weekend days (Friday - Saturday), and "rest days" (Sunday).
Generally speaking though, public transport in Paris never stops. When the Metro/RER stops working, their journeys are replaced by night buses (Noctiliens), marked with a starting N on the bus number.
From your premises I assumed you were landing in some god-forsaken place like Beauvais. Instead arriving in Bercy means that you are already in Paris. The Bercy Metro station is served by the Metro 14, which takes you towards the centre, and the Metro 6 which takes you all-around the city to its west side. Here are the first and last trains from Bercy on Monday 22/12. So I would say pick any hostel with good reviews and go for it.
It really depends on the hostel you book. Some hostels in Paris have an arrangement with a nearby pub, where keys need to be obtained after a given evening hour (ranging from 20.00 till 24.00). If the pub closes there is no way of entering the hostel. Some hostels have a midnight reception. So you should really make sure which hostel you choose and communicate upon making a reservation that you'll arrive late.
Some hotels now have automatic vending machine installed which allows you to get your key anytime. Here you need to pay the hotel at "checkin".
An other alternative is to try airbnb or only-appartment where you book a bed with locals, with whom you need to make arrangement anyway. Usually an extra fee for late checkins are applied.
When you are past the last metro/bus, you can always rely on either a taxi or Velib
