Some 80 graves have been desecrated with swastikas at a Jewish cemetery in eastern France, local officials say.
The damage was discovered on Tuesday, ahead of nationwide marches against a rise in anti-Semitic attacks.
It occurred at a cemetery in the village of Quatzenheim, on the night of Monday into Tuesday, town hall officials told the franceinfo website.
President Emmanuel Macron has condemned anti-Semitic abuse after a prominent intellectual was targeted.
Police stepped in to protect the philosopher, Alain Finkielkraut, after he was bombarded with insults and anti-Jewish taunts by a group of “yellow vest” protesters in Paris at the weekend.
Mr Macron visited the cemetery to inspect the damage on Tuesday, before he heads to the Paris Holocaust memorial.
“It’s important for me to be here with you today,” he told local leaders and members of the Jewish community.
Several local officials denounced the desecration on social media.
Mr Castaner has warned that anti-Semitism is “spreading like poison” in the country, with a series of anti-Jewish incidents reported in central Paris last weekend.
These included post-boxes featuring a Holocaust survivor’s portrait being vandalised with swastikas.
Official data suggested there had been a 74% rise in anti-Semitic attacks in France last year.
Jewish groups have also been warning that a rising far right across Europe has been promoting anti-Semitism and hatred of other minorities.
Crime data from Germany released last week revealed that anti-Semitic offences had increased by 10% over the past year – including a 60% rise in physical attacks.
Attacks have been blamed on both the far right and Islamists.