L'Aiglon ou le Lys is a generic wargame at the time of the Napoleonic Wars. "Blue" against a coalition of "Grey" and "Yellow". The rules are based on those of "1812: Les Arapiles" published in a previous issue of Casus Belli.
Published in three parts: Casus Belli #43 and #44 for the 2 part map, Casus Belli #45 for the specific rules.
You need Casus Belli #41 for the Standard Rules.