'Le Bureau' is a cooperative that acts as an intermediary for people to buy domain names; it's not yet a domain registrar: an organisation that can register a domain name on the behalf of a registrant (you) with a registry.
Examples of registrars: GoDaddy, Namecheap, or Gandi.
Examples of registries: DENIC in Germany, Nominet in the United Kingdom
In their FAQ, Le Bureau explains that the aim is for Le Bureau to become a registrar.
From their FAQ:
Actuellement, LeBureau.coop agit en tant que revendeur de noms de domaine, le temps de développer son offre. L'objectif à terme est de devenir un bureau d'enregistrement et de traiter directement avec les registres.
At the moment, LeBureau.coop acts as a reseller of domain names [...]. The long-term aim is for Le Bureau to become a registrar so it can deal directly with registries.
Why do I think what Le Bureau does is interesting?
Most registrars are for-profit businesses or publicly listed companies; meaning that they cater to the interests of owners or investors.
Some of us might have seen registrars change hands, or might have experienced a decline in the quality of customer service over time, or erratic price increase, like when Gandi got acquired a few years ago (for the second time).
Le Bureau is a cooperative, not a for-profit, neither a non-profit; meaning that users can buy shares of the cooperative to become voting members (sociétaires).
There are no investors; the cooperative cannot be sold or acquired.
Sociétaires govern the cooperative, and once Le Bureau becomes a registrar of its own, users will govern the entity which registers and hold their domain names.
More information at https://lebureau.coop (in French).
Sources: https://www.icann.org/resources/pages/what-2013-05-03-en https://www.icann.org/resources/pages/registries/registries-en