Hostel is a good choice for those who have to save. However, remember that at almost the same price, a number can be found in a low-cost hotel, especially in remote areas where most hosts are located.
The hosts have a maximum residence (usually less than a week) and a curfew (usually around 2.00). But in many institutions, you will be given a key or a magnetic card.
Most hosts accept pre-referencing, including all three leading networks: FUAJ (at Hostelling International), UCRIF and MIJE. There are only two HI hosts in Paris (both FUAJ, Fédération Unie des Auberges de Jeunesse): Cité de Science and Léo Lagrange, both at the edge of the city. We need a membership card to settle in them, but we can put it right there.
It's better to book in summer. From anywhere in the world, this can be done through the electronic system of hosting. The Paris office FUAJ is on Branthôme Street, 9 near Pompidou Center. The second largest network of hosts, UCRIF (Union des Centres de Rencontres Internationaux de France), focuses on group accommodation.
Once again, we have only the most convenient hosts on the list, but on the Internet, you will find others, including the ones that will be free. In the main office of UCRIF, which is located in the 2nd district, on the street de Turbigo, 27 (day to Friday from 9 a.m. to 6 p.m.); Etienne-Marcel subway), you will be sent to places.
Third network, MIJE (Maison Internationale de la Jeunesse et des Etudiants) owns three hosts located in historical buildings Mere quarter♪ All three are very popular, and there's a lot to be booked long before the trip.