French police are searching several sites run by dairy group Lactalis as part of an ongoing investigation into a baby milk scare.
More than 12 million boxes of powdered baby milk have already been recalled in 83 countries following a salmonella outbreak.
Lawsuits have been filed by parents who say their children became unwell after drinking the formula.
Sites raided include a factory in Craon, north-western France.
The factory was closed last month after it was thought the contamination started in one of its drying towers.
Lactalis spokesperson Michel Nalet confirmed the police presence. “As we have said before, Lactalis is cooperating with justice authorities and will provide everything necessary for a smooth conduct of the investigation,” he told AFP news agency.
At least 37 babies have been affected in France.
The Lactalis group is one of the world’s largest producers of dairy products, with annual sales of €17bn ($21bn; £15bn), It has 246 production sites in 47 countries and employs 15,000 people in France alone.
What does the company say?
Lactalis has said they believe the contamination was caused by renovation work at their Craon factory.
In a recent interview in French newspaper Journal du Dimanche, chief executive Emmanuel Besnier denied the firm had attempted to hide the outbreak.
He also promised the company would compensate any families affected.
What are the dangers?
Salmonella can cause diarrhoea, stomach cramps, vomiting, and severe dehydration. It can be life-threatening, especially in young children.
What products are affected?
The Picot, Milumel and Taranis brands have been recalled.
Last week a company spokesman told the BBC that all the countries affected had been informed, in Europe, Asia, Latin America and Africa. The UK, US and Australia were not affected, he added.
The government crackdown
France’s agriculture minister said products from the Craon factory will be banned indefinitely while the investigation is still ongoing.
The French government has warned the company it must expect penalties over its handling of the affair.
They also threatened to impose sanctions against retailers last week, after it emerged that several major supermarket chains had continued to sell products that could have been contaminated.