What if France were to use America’s electoral system?

If France were to use America’s electoral system, Marine Le Pen might be on course for victory, says The Economist.

Method:

The American system can be translated to France with some straightforward arithmetic. Considering the 18 French regions—13 in metropolitan France and five overseas—as analogous to American states, each one gets two senators. Maintaining the American ratio of 4.35 members of the lower chamber for each of the 36 senators, the French House of Representatives would have 157 seats. Since each region is guaranteed at least one representative in the lower house, 139 seats would be allocated on the basis of population using the method of equal proportions. Finally, each region would be weighted in the electoral college by the total number of its representatives in both chambers.