The Capedia Sources page should help you determine the quality of the information and the database. https://www.capet.org/sources.php
A quick review reveals that there are none. They mention "the classics," which is to say the doyens of French aristocratic genealogy: Anselm de Guibours (Père Anselme), born 1625; La Chesnaye-Desbois, born 1699; Chaix d'Est Ange, b. 1863. Capedia, however, are not specific about how they're used. Along with this they mention "...une sélection des meilleurs ouvrages généalogiques..." with a link that leads back to the same page. More worryingly, another cited source is "...la participation spontanée de 1,178 passionnés d'histoire et de généalogie." - which is to say that there are about 1200 volunteers that have entered information at random.
I wouldn't cite this site at all, not even as a place to start for research. It's completely random and there's no saying where anything came from. All the works actually cited (the above authors) are available, I believe, on Google books or Gallica (the digital version of the national library of france at gallica.bnf.fr). Père Anselme, ancient though his work is, did make a habit out of quoting original documents at length, so it's worth checking out his rather massive volumes.
