France has blamed Iran for a cyberattack that disrupted refrigeration systems in hundreds of supermarkets last month, escalating the diplomatic response to an incident that affected food retailers across the country.

Paris prosecutors said on Monday that Iran’s Islamic Revolutionary Guard Corps was behind the October 12 attack, according to the Associated Press. The incident caused refrigerator temperatures to rise and affected about 700 of France’s 10,000 supermarkets.

French Foreign Minister Jean-Noël Barrot said Iran’s ambassador would be summoned. He also said France would seek European sanctions against those responsible. Prosecutors have opened a formal judicial investigation into suspected organised cybercrime carried out in the interests of a foreign power.

According to prosecutors, investigators found the attackers had used Farsi and internet-protocol addresses linked to devices in Iran. They are seeking international arrest warrants. Those details are part of the French investigation; the public statements reported so far do not provide a full technical account of how the attackers accessed each retailer’s systems.

The case highlights the potential consequences when digital systems that control ordinary commercial equipment are compromised at scale. The affected systems were supermarket refrigeration controls, not the national electricity grid. The investigation and any coordinated European response are now the next steps to watch.