That picture is hard to see, but that is not a Légion d'Honneur. Notice in this higher quality version that it has fleurs de lis between the arms of the cross, something the Légion d'Honneur never had.

https://www.bertrand-malvaux.fr/p/553/portrait-d-un-capitaine-de-la-legion-de-mirabeau-de-l-armee-de-conde-vers-1792-1795-revolution.html

Judging by the colour of the ribbon, the shape and colours of the cross, the chronology, and the presence of the fleurs de lis, I can identify that medal as the Ordre de Notre-Dame du Mont Carmel. Here is a picture of what it looked like.

https://data.bnf.fr/fr/13369142/ordre_de_notre-dame_du_mont-carmel/