An inquiry accused Nestlé and French officials of hiding the company’s practice of filtering Perrier water it labels “natural.” The head of Nestlé has suggested that human activity is making pure water scarcer.

For more than 120 years, the French brand Perrier has produced some of the world’s most recognizable sparkling mineral water, its teardrop-shaped green bottles and light, fizzy bubbles synonymous with European refinement and good taste.

Recently, however, the brand has found itself embroiled in a decidedly inelegant scandal involving food and drink regulations, the definition of “natural” water and, this week, accusations of a cover-up that reached the upper levels of the French government.

At the heart of the issue is the marketing of Perrier as “natural mineral water,” a term whose use is strictly regulated by France and the European Union.

French regulators and independent consumer watchdogs have accused Nestlé Waters, Perrier’s French parent company, of using filters and ultraviolet sterilizers for years to treat the water it bottles from wells in Provence. The methods ran afoul of French and E.U. regulations, they said, and altered the water to the point that it could no longer be labeled “natural.”

This month, officials in the Gard region of southern France, where Perrier’s water is sourced, ordered the company to remove its water filters within two months while authorities decide whether to demand that Perrier change its labeling.

The dispute widened this week when the French Senate released the findings of an investigation that found Nestlé had concealed its treatment of Perrier and other brands of bottled water with the help of the French government, which the report accused of covering up “illegal practices.”