France was obviously divided into factions before Macron's election, so this article is actually  pretty silly. 
Macron's victory was arguably the least divisive outcome possible. Certainly much less divisive than a win by LePen or Melenchon would have been. Even Fillion would have fired up the divisions between right and left. 
The centrist Macron has the best chance of uniting the factions because his policies will be based more on pragmatism than left or right ideology.