This scenario attempts to being about the opposite of Operation Sealion. Instead of trying to attack Britain the aim is to not to attack Britain at all or to use the least amount of force possible. The deployment of land forces on the British Isles is strictly to be avoided.
In this timeline, France manages to unify continental Europe through force in the mid 1800's. At that point is there any way for the new French Empire to stop Britain from attacking them? They have no interest in conquering Britain and even if Britain dislikes them France is willing to just leave them be so long as no attacks come from the Isles.
The situation could very roughly be seen as like Napoleonic France and the British Empire except that in this timeline Russia has lost a war to France. Russia still exists but is part of the Continental System. The POD is far enough back that Napoleon is not the one leading France so feel free to suggest any traits that could be helpful for the alternate French Emperor.
In this timeline, France manages to unify continental Europe through force in the mid 1800's. At that point is there any way for the new French Empire to stop Britain from attacking them? They have no interest in conquering Britain and even if Britain dislikes them France is willing to just leave them be so long as no attacks come from the Isles.
The situation could very roughly be seen as like Napoleonic France and the British Empire except that in this timeline Russia has lost a war to France. Russia still exists but is part of the Continental System. The POD is far enough back that Napoleon is not the one leading France so feel free to suggest any traits that could be helpful for the alternate French Emperor.