The 49.3

 For British people, the nearest equivalent of the 49.3 is the Parliament Act, where the government can push legislation through even if it is fiercely and strongly opposed. 

Why does this matter? 

Well successive governments in France have tried to reform the pensions system. The current retirement age is 62, for women and for men. Read and weep, British friend. Some people have special retirement arrangements that allow them to retire early, sometimes as early as 52. The government says that with a falling birth rate and an aging population profile, and healthier elderly people, France cannot continue with this retirement regime. They want to raise the age to 64. Read and weep, British friend.

So there have been successive demonstrations and strikes, and strong opposition in Parliament. Macron does not want to be yet another President who tried and failed to seize the pensions nettle, so yesterday, unexpectedly, after saying repeatedly that they wanted to avoid using the 49.3, Mme Borne invoked it, the Socialists sang La Marseillaise ("contre nous de la tyrranie l'étendard sanglant est levé" - against us is raised the bloody flag of tyranny) and riots ensued in Paris, Rennes, and probably Marseille and Toulouse.