French Prime Minister Manuel Valls pledged to engage in “combat against antisemitism” in a rousing pre-Rosh Hashanah address to the Nazareth Synagogue in Paris last week.

Mr Valls said “a vast campaign” against all forms of racism would be launched by his government this autumn.

“Every prefect, every state prosecutor, has been instructed to punish these crimes with the full force of the law,” he thundered. “Today, the fight has to be fought again.”

France must not forget the Dreyfus affair, he said, nor the murders of Ilan Halimi in Paris in 2006, the killings in Toulouse in 2012, or the atrocities committed in a Parisian supermarket in January.

In Paris’s oldest Ashkenazi temple, built with King Louis XVIII’s personal blessing and Baron James de Rothschild’s beneficence, Mr Valls stood in front of a giant chanukia candalabrum and summoned his formidable rhetorical powers, well aware that this year has possibly been the worst for French Jews since the Nazi occupation, and that many are thinking of leaving.

Mr Valls pleaded with French Jews to stay. “France would lose an essential part of herself, without her Jews...We can’t condemn those who leave for Israel, but their place is here.”

Economics Minister Emmanuel Macron has just come back from Israel, where he sought to convince French entrepreneurs and investors to return home. Israel has been doing all she can to lure Gallic Jews to the Holy Land, even organising aliyah fairs in Paris.

Mr Valls’s audience was mostly reassured, despite continuing increased levels of antisemitic attacks. Synagogues and Jewish schools in France continue to have formidable military protection.

After the Hyper Cacher supermarket attack in January, Israeli Premier Benjamin Netanyahu called for the community to move to Israel. Mr Valls responded by pleading with French Jewry to stay, saying: “Without her Jews, France is not France.”