Personally I can't believe no one has thought or suggested this before. The challenge, as the title suggests, is to get Charles Maurice de Talleyrand-Périgord, France's most famous diplomat and sometime clergymen, elected to the Papal throne. Obviously he'd have to remain a cleric, but that's the only legal block. How could this be done? Maybe the French captures the College of Cardinals at Pius VI's death in 1799 and forces them to elect a Frenchmen (Talleyrand)? Or Napoleon decides to depose Pius VII and creates his own Anti-Pope in Avignon? Or another scenario I've yet to think of?