Have only looked at a couple of 11mm French revolvers, never fired one. Have worked with a 10.4Italian and a couple of .450 BullDog types...on a guess, the French was actually better finished, but don't believe it would be any stronger. Won't say a smokless load couldn't be made to work, but will say that it's not going to be easy to stay within acceptable pressure. Personally, I'd stay with black or RS Pyrodex.
Fiocchi still loads the 10.4 and the .450, and perhaps a lesson from them would help. Both are smokless loads...the powder isn't a match for anything seen commercially. The bullets are made with minimal bearing area, are smaller in diameter than the bore of the examples I've measured (and yes...they shoot pretty poorly), and are light for their caliber. Those are "tricks" to keep pressure low.
If you "just gotta" then keep the above in mind: small diameter, short bearing area, low weight help keep presure down (also keeps smokeless from bruning worth a rat's rump, but that's the idea). The above pretty well describes a round ball; a good place to start with BP as well.