A French magistrate has opened a fraud inquiry into mineral water giants Nestle and Sources Alma over suspicions of illegal processing of water, according to a source close to the investigation.

The source said the magistrate had gone against the recommendation of prosecutors in launching the new investigation into the companies.

The inquiry follows formal complaints made by the Foodwatch watchdog against Nestle Waters — whose brands include Perrier, Contrex and Vittel — and Sources Alma, France’s biggest mineral water producer.

Foodwatch has led mounting pressure on the firms in recent years over their production methods.

In 2024, Nestle Waters admitted using banned filters and ultra-violet treatment on mineral waters, which must be processed naturally by law.

Foodwatch accuses the companies of misleading consumers over the water in the latest complaint taken up by the magistrate.

Another consumer group, CLCV, has also registered complaints, which are being studied by magistrates.

Foodwatch director general Karine Jacquemart hoped the investigations would “smash the climate of impunity” surrounding the companies and “shed all light on responsibility of Nestle Waters and Sources Alma as well as the role of public authorities and particularly the Government.”

French media have already reported that the Prime Minister’s office and President’s office had in 2023 recommended letting Nestle carry on with the microfiltering of water despite warnings from the Government health service.

Director-general of health, Jerome Salomon, had called for the suspension of Nestle’s operations permit at its sites in the Vosges region of eastern France and production of Perrier at Vergeze.

President Emmanuel Macron has denied giving in to lobbying by the Swiss food giant.

Nestle Waters paid a two-million-euro ($2.2m) fine in September 2024 to avoid legal action over the use of illegal water sources and filtering, but says the filters it uses now are allowed by the Government and that its water is “pure”.

Sources Alma had also previously been under investigation by prosecutors.

The Government’s role in the water scandals has been under investigation by the French Senate since November. The Senate Commission has already criticised the Government.

Alexandre Ouizille, the head of the commission, welcomed the criminal investigations.

“Each hearing we hold confirms to us the failure of ministries and administrative authorities,” he said.

© Agence France-Presse