Hi Nightmoves and welcome to the forum.
If anthracite (boulets) is available in your area and at a good price, try it and see how it works in your specific stove. Check if the stove you'r looking at is made for ""tous les combustibles, soit bois/charbon)"" or for some specific ones. If you can send some (beaucoup) photos of the stove, it's always welcomed on the forum and that helps us to help you
. Anyways going to anthracite is a good move if the ant is available in your area.
About the flue pipe and chimney installation, it would be Safer for you to verify the codes requerements in your area and in France. As an example, here in Québec the stoves installations codes differ from those in the USA, so better to check before...........
Salutations du Québec.
P/S Maybe start a new thread in Hand Fired Coal Stoves?