The demonstrators at Place de la République in Paris were chanting, weirdly, in Italian: “Siamo tutti antifascists,” — “We are all antifascists.” In French, they targeted their chief enemy, the president: “We are here, even if Macron doesn’t want it.”

Watching them were ranks of massed riot police, who, in the French policing tradition, made no effort to mingle with the crowd and defuse trouble, but instead stood waiting for the moment to unleash their tear gas and batons. The crowd were waiting for it, too. “ACAB,” they chanted, the English abbreviation for “All Cops Are Bastards”. “A-ca-buh”, it came out in French.

Then someone set a dustbin on fire — the perfect Instagram image — and other demonstrators began filming it. They knew they were taking their places in a glamorous Parisian tradition, stretching from 1789 through 1944 and 1968. At last the police advanced, and people began chucking bottles.