French Jews were only partly reassured when more than 100,000 people, including the prime minister, Élisabeth Borne, and two former presidents, turned out to demonstrate in Paris last month against antisemitism and in defence of the secular republic. Why did the president, Emmanuel Macron, not attend, many asked? Where were the leaders of France’s Muslim community? And where were the cultural, intellectual and sports celebrities so often eager to take a public stance on a worthy cause? Since Hamas fighters poured into Israel from the Gaza Strip on 7 October, slaughtering around 1,200 Israeli men, women and children, a wave...