Do not think that just because there is a European Union that Europe is united. Nothing could be further from the truth. The historical pastimes of Europe have always been national rivalries and war between states and that has not changed. What has changed is the method.
With the advent of weapons of mass destruction, Europe realized that conventional war is no longer a viable option, so they have transitioned into economic warfare. The entire European project, including the Euro, boils down to a competition for supremacy between Germany and France; and France is losing.
Within the next 10 years, Germany will control the French national budget, or anyway, it will make great progress towards being able to do so. As this progress advances, there will be increasing calls within France to exit the EU, just like Britain, though this will be far more complicated, since France uses the Euro, but ultimately, I think they will secede.