In mid-August, as London's neighbourhoods underwent violence, looting and fire, France's Jews looked on with a familiar disquiet. Jews were in no sense the target of this summer's rioting, but a decade ago, something similar went wrong on the streets of Paris that has not been put right since. The present era of European street violence began with widespread assaults on Jews around Paris in the autumn of 2000, the year of the so-called "second intifada" in Israel. The following year saw riots in Oldham and Rochdale — overshadowed in retrospect by the destruction of the World Trade Center just weeks later.

 
No rest: A desecrated gravestone in the Jewish cemetary of Brumath, France, November 2004 (Getty)

There were 744 acts of anti-Jewish violence and threats in France in 2000, the worst year since the war. While these were, beyond any shadow of a doubt, anti-Semitic acts, they were not perpetrated by the sort of anti-Semites against whom French people had steeled themselves to be vigilant. Violence was particularly intense in those north Paris neighbourhoods, such as Sarcelles and Garges-lès-Gonesses, where an established and ageing Jewish population, much of it descended from North African immigration of the early 1960s, lived at close quarters with newer Muslim immigrants, many of them young. The attacks were stemmed by an aggressive government response starting in 2002, but they have never died out. The years 2004 and 2009 were worse. They form the backdrop to a more general sense of being ill-at-ease, or no longer quite so at home, that many French Jews describe.

Paris has more Jews than any country in Western Europe. It also has more Arab Muslims. Clashing visions of how the French state ought to respond have led to a divergence of interests between the two groups. But while the Arab population is rising rapidly, the Jewish population is ageing and shrinking due to emigration, intermarriage and small family size. It has fallen to under half a million, according to the authoritative Hebrew University demographer Sergio Della Pergola. It is now hard to teach the Holocaust in schools, due to harassment and disruption from mostly immigrant students. A third  of Jewish students have abandoned the state school system for Jewish schools, while another third go to Catholic ones — more for reasons of security than pedagogy. Regularly scheduled, robustly attended demonstrations question the legitimacy of the state of Israel. 

But a problem that France presents at its most intense is not exclusively a French problem. The senior politician of the Dutch centre-Right, Frits Bolkestein, has worried aloud that Holland's unassimilated Muslims may make the country a dangerous place for its 40,000 Orthodox (and therefore visible) Jews. In Germany, the Left party has held fraught internal meetings to discuss whether its members' passionate anti-Israel sentiments were shading over into anti-Semitic ones. 

France's behaviour towards its Jews in World War II has for decades served as the lodestone for its political ethics. For a quarter-century after the war, an official silence surrounded the collaboration of France's wartime Vichy government with that of Nazi Germany. Since the early 1970s, when the American historian Robert Paxton and the documentary filmmaker Marcel Ophüls revealed that collaboration in detail, discussion of France's misdeeds has been wide-open. But it has the power to fascinate and wound. Two major movies about the Holocaust were showing in French cinemas over the summer — the American film Sarah's Key and the French-made La Rafle, which describes the night of July 15, 1942, when thousands of Jews, including children, were rounded up by French authorities. They followed a spat over whether to celebrate the 50th anniversary of the death of Louis-Ferdinand Céline, arguably France's greatest 20th-century novelist but certainly one of its most notorious literary anti-Semites. 

France looked at the record of World War II and found it so unspeakable that it insisted on stamping out the merest glimmer of the doctrines that had made such things  possible. It was not the only country in continental Europe that did so. But there was an added drama to the French state's relations with France's Jews. For the first two decades of Israel's existence, France was its most important ally. The two countries even cooperated to develop their nuclear weapons programmes. But after Israel fought the Six-Day War against a coalition of Arab powers in 1967, France's president Charles de Gaulle withdrew his support, and in terms that made it seem his real gripe was not with Israel but with Jews, whom he called "an elite people, sure of itself and dominant". Nonetheless, for decades after the 1970s, remembering the Holocaust in a dignified and appropriate way (le devoir de mémoire, as the French called it) was the core "spiritual exercise" of France — in its schools and on its public days of remembrance. Jews wound up,  willy-nilly, at the centre of France's moral system.