Most of the time, sources are provided in Les Décodeurs' fact-checks. According to our assessment, Les Décodeurs' fact-checkers give most of the time details to the readers, so that they are able to replicate the fact-check by their own means.
Fact-checks are written in a pedagogical way and the team try to explain its work.
Besides, Les Décodeurs have a specific policy on sources, which is mentioned here: : http://www.lemonde.fr/les-decodeurs/article/2014/03/10/la-charte-des-decodeurs_4365106_4355770.html
This document mentions, in its sixth section: "Our articles explicitly mention the source of a fact or a number. As soon as a fact, a number, a source, is available on the Internet, we indicate it by a link".
3a marked as Partially compliant by Laurent Bigot.