The alleged rape last weekend of a 12-year-old Jewish girl by boys who hurled antisemitic abuse at her has ignited simmering tensions in France over attitudes toward the largest Jewish community in Western Europe.

President Emmanuel Macron, a centrist whose decision to call snap elections this month shocked even his closest allies, responded by denouncing the “scourge of antisemitism” in French schools. The prime minister, Gabriel Attal, urged politicians to “refuse the banalization” of hatred toward Jews, a thinly veiled attack on Jean-Luc Mélenchon, the ardently pro-Palestinian leader of the left who on June 2 called antisemitism in France “residual.”

There were more than 360 antisemitic episodes in France in the first three months of this year, or an average of four a day, an increase of 300 percent over the same period last year, the government said. In the most recent one that shocked the country, the three boys are said to have dragged the girl into an abandoned building where she was repeatedly raped and insulted.

The three boys, ages 12 and 13, one of them previously known to the girl, are being investigated for rape, death threats and insults “aggravated by their link to the victim’s religion,” a prosecutor’s statement on Wednesday said. Two of them have been placed in pretrial detention, it added.

The place of Jews in French society has emerged as a prominent theme in the election because the once-antisemitic National Rally party of Marine Le Pen, whose anti-immigrant position lies at the core of its fast-growing popularity, has been one of the most emphatic supporters of Israel and French Jews since the Hamas-led terrorist attack of Oct. 7 on Israel.

Mr. Mélenchon’s France Unbowed, by contrast, has been vehement in its denunciation of Israel’s military operation in Gaza as “genocide.”