Legal representatives in France have launched an inquest into Nestlé’s treatment of its mineral bottled waters.

According to national newspaper Le Monde, the investigation has been launched by prosecutors at the Épinal law courts in north-eastern France.

Speaking to the Agence-France Presse, local prosecutor Frédéric Nahon said the inquiry was initiated after it received a complaint from the national health regulator, Agence Régionale de Santé.

The examinations “are still in progress”, Nahon said, “in particular to establish whether the label ‘natural’ mineral water is misleading or not”.

It is unclear when the investigation opened.

Last week, Nestlé admitted to Le Monde that it had violated French law by using multiple purification treatments on bottled waters labelled as “mineral water”, which included products sold under the Perrier and Vittel brands.

It is illegal to use purification techniques on goods labelled as ‘spring’ or ‘mineral’ water in France, as they are already considered safe to drink due to being sourced directly from protected natural springs.

In a statement released last week, Nestlé said it had “used microfiltration at our Waters sites at a finer level than was previously recognised by the French authorities.”

The Swiss giant added it had specifically adopted “activated carbon filters and ultraviolet systems which, though permitted by other jurisdictions, are not in line with application French natural mineral water regulations”.

The Contrex bottled water maker said it had “proactively brought this matter to the attention of the French authorities” in 2021.

Nestlé added it had offered “several options to ensure compliance moving forwards”, such as “submitting evidence to demonstrate that our use of the finer level of microfiltration at our Waters sites does not disinfect or impact the unique characteristics of our natural mineral waters”.

While it said the national authorities had “validated” its “finer microfilter” treatment at the time, it added that “the treatments that were not permitted” had since been removed.

According to the company, its Perrier, Vittel, Contrex and Hépar brands are now fully compliant with French laws around natural mineral water production.

Just Drinks has asked Nestlé to confirm when it stopped using the purification treatments on its mineral and spring bottled waters.