What would jefferson have to do if france took control of new orleans?

Louisiana was a massive territory covering, much of the interior of the continent. Although it was sparsely populated by Europeans, except for in the extreme South. New Orleans, the capitol of the territory, sat across the end of the Mississippi river, which drains the land between the Rockies and the Appalachians. In particular the highly navigable Ohio river drains into the Mississppi and any goods coming from the Ohio which want to get out onto the ocean, and the international market, needed to go through New Orleans. In the nearly two decades between American independence and the Louisiana Purchase, the US and Spain had been in frequent negotiations over right of passage for American trades through New Orleans. 

Napoleon acquiring Louisiana could potentially upset American plans. Spain was the weaker power and the Americans felt that they could get a good agreement for passage of American trade, or even force Spain to give up Louisiana to them. But France was one of the two world superpowers and seemed a lot stronger. Napoleon was an arch-imperialist and Americans feared that if he controlled Louisiana he'd mean to keep it. Which he did. He had dreams of re-establishing a French overseas empire and Louisiana would be part of that. Fortunately for American dreams of manifest destiny, events quickly changed Napoleons minds. Shortly after the French regained control of Louisiana, the Haitians defeated the French force sent there to try and reestablish control of the island. Haiti proclaimed its independence and without the major money maker of Haiti there was little reason to hold on to Louisiana. Napoleon decided to cut his losses and make some quick cash by selling Louisiana to the Americans who were eager to buy it.

Contributing factors  leading  to the harlem renaissance were the great migration of african americans to northern cities, which concentratedambitious  people in places where they could encourage each  other, and the first world war, which had created new industrial work opportunities for tens of thousands of people.