They marched through the narrow streets of Lyon’s medieval old town, about three dozen of them, emboldened after the French far-right gains in the European elections. Masks covering their faces, they wound past the hidden passageways that provided cover for the resistance during the second world war, chanting: “We are fucking Nazis” and “Islam out of Europe”. For some in this French city, last week’s far-right demonstration, captured on video, was a chilling reminder of just how much is at stake in the snap parliamentary elections that could see the French far-right lead government. “The consequences would be catastrophic,” said...