The Ark is a space colony created by a group of former Earthlings who cut all ties with their home planet. The first 6000 people left Earth in the year 2051 AD. Not all of these first people survived the trip. Something shady happened during the first trips, according to Matthias Binger. People in the Ark were not very popular with the people of Paris 1).
On the Ark there were regulations to get two kids to continue the cycle 3).
See also L'Arche