François Fillon is the new uncontested leader of the conservatives in France. After his resounding win in the primaries, the former prime minister is already training his sights on a bigger prize: the presidential palace. His most likely opponent will be the far-right leader Marine Le Pen. This is all the more likely because the ruling Socialists are not only deeply unpopular but also deeply divided - so much so that the president and prime minister locked horns in public this week.