Procession arrives at Place des Terreaux with a banner reading, “Against Antisemitism, for the Republic,” during the march against antisemitism, in Lyon, France, June 25, 2024. Photo: Romain Costaseca / Hans Lucas via Reuters Connect

Two young men have been placed under formal investigation in France for planning a “deadly and antisemitic“ attack, the counterterrorism prosecutor’s office (PNAT) said in a statement on Sunday.

The suspects, a 22-year-old engineering student and an unemployed 20-year-old who are brothers, were arrested last Tuesday after police found a semi-automatic firearm, a bottle of acid and an ISIS flag in their car during a roadside police stop near a prison in northern France, PNAT said. It gave no details about the nature of the planned attack or its target.

The two are being investigated on charges of criminal terrorist conspiracy and possessing a weapon in connection with a terrorist undertaking, and have been placed in pre-trial detention. The PNAT did not release the suspects’ full identities.

Concerns about possible attacks against ⁠Jewish communities ​around the world have risen ​following US and Israeli attacks on Iran and a subsequent response from Tehran.

A gunman crashed his truck into a Detroit-area synagogue on Thursday, while in Europe an explosion caused minor damage to a Jewish school in Amsterdam on Saturday and another explosion caused a fire at a synagogue in Belgium on Monday.

The French interior ministry reinforced security around Jewish places of worship in early March.

The French authorities said jihadist propaganda was found on the suspects’ digital devices and one of the brothers had filmed a video pledging allegiance to ISIS.

Governments and human rights advocates have noted a rise in antisemitism since the 2023 Hamas attack and Israel’s war on Gaza.

France‘s human rights commission, the CNCDH, has said antisemitic acts in France tend to increase after Israeli army operations in Palestinian territories. Antisemitic acts surged to a record high after the 2023 Hamas attack, but fell 16% in 2025 compared with the year before. However, they remained well above pre-2023 levels.