Apparently Napoleon had continued grand ideas about invading India, either overland or by ship from Egypt. He tried to ally with Ottoman Turkey and Persia to this end. The British tried to ally with Afghanistan and Persia to defend from a theoretical French invasion.
The invasion via ships from Egypt is not going to happen, so would it be possible or Napoleon to march an army into India Alexander the Great style?
If so what would be the outcomes of an 1812 "India expedition" instead of a "Moscow expedition"? Would Napoleon be bold enough to try to lead the invasion force himself and hope his Brothers can keep his power secure in Paris? If he doesn't lead it himself and it somehow actually works then he does run the risk of the glory of someone else outshining his. Or would he send a loyal underling to do it for him?
Assuming a best case Scenario where the French have things calmed down enough in Europe to send the resources to such a far off location. ( Either better relations with Russia or avoiding the Spanish Ulcer ) They have nominal alliances with Persia and Turkey. And Russia and Persia have reached a peace. ( I know having all those happen together is highly unlikely, but those would be the basic preconditions for such an expedition I'd imagine. ) It's 1812, France rules the continent and has no immediate pressing threats, atleast any it can't deal with easily. There is a French corps of 30,000 men under Marshall Ney along with 30,000 Persian troops, most of which have been trained by the French mission to Persia.
What happens now?
So the first big question is can this force even march to Afghanistan semi in one piece?
I'd be inclined to say maybe with a lot of resources poured into keeping the army fed and with water.
Im assuming the Afghans would not take kindly to the Franco-Persian force marching over it's country ( Persia is likely offered expansion at the expense of Afghanistan too for it's help ), so the second question is can the Franco-Persians beat the Afghans? I honestly am not sure at all. Though the Persian forces might be more able to deal with the locals than the totally alien French would. So if, and that's a big if you now have a force of 15,000 French and 10,000 Persians get to the territory of the Sikhs. What happens next? I really have no idea. Though I'd be inclined to think the French won't get far since the British could likely field 250,000 British and Native troops to block any French attacks. But the French if they got that far could give the British some serious headaches if they form alliances with some of the native States in India.