Comparaison des élections présidentielles de 2012 en France et aux Etats-unis par Manu Wallerstein.
Binghamton University - Fernand Braudel Center : Commentaries
►http://www2.binghamton.edu/fbc/commentaries/index.html
However, if Melenchon gets a large vote and Hollande is nonetheless in the second round, two things will be true. One, there will have been a clear message to the Socialists that politically they must move left. And secondly, most Melenchon voters will vote for Hollande on the second round. On the right, however, most LePen voters will be reluctant to vote Sarkozy, and the Front National will not recommend this. Were they to do so, they would undermine the very basis for their existence.
The French system seems to work better for the radical left. The U.S. system seems to work better for the far right. But this is primarily because of different electoral rules.