The title should be sorted as "Des Milliards de Kakuro", not "Milliards de Kakuro, Des". While "des" is an article in French, it is a partitive article that can mean "some" or "any" in English (depending on context). Only definite and indefinite articles are to be disregarded when sorting titles.
I was unable to immediately find concrete proof of how French libraries sort their titles, but French Wikipedia does not treat "des" as an article to omit when sorting titles. Example category (for American novels adapted for television):
https://fr.wikipedia.org/wiki/Cat%C3%A9 … 3%A9vision
I made the same mistaken assumption about "des" myself when I first submitted this game to Redump, but I posted a fix thread to rectify it (though I admit that my own wording back then was not entirely accurate as I did not fully understand it at the time):
http://forum.redump.org/topic/43168/fix … wip-queue/
Further suggested reading:
https://www.lawlessfrench.com/grammar/p … e-article/
https://www.loc.gov/marc/bibliographic/bdapndxf.html ("des" not listed as a definite or indefinite article in French)
The wiki should also be updated to remove "des" from the list of French articles to check for at the start of a title:
http://wiki.redump.org/index.php?title= … tion_Guide