France's prime minister said on Thursday he would look very carefully at any attempted ownership change at L'Oréal especially if an international investor sought to buy the world's biggest cosmetics firm.

The death of billionaire Liliane Bettencourt on Sept. 21 has focused attention on how L'Oréal's founding family and major shareholder Nestlé would manage their stakes in the company.

Bettencourt's family owns 33 percent of L'Oréal. Relatives including her daughter have managed the stake for several years since a court found she was suffering from a form of dementia.

Nestlé retains a 23 percent stake in the company. It has said it has no intention to sell its stake.

"We will be attentive," Edouard Philippe told France 2 television when asked how he would react if the company were to be subject to an overseas bid. "I don't know if it can be described as a strategic asset," he said. "Without a doubt it's an extremely important asset so I will be very mindful."

In the wake of Bettencourt's death, a 43-year-old agreement between the family and Nestlé not to increase their stakes will expire after six months. There were no restrictions on reducing the stakes.

Bettencourt's only daughter, Françoise Bettencourt-Meyers, who sits on L'Oréal's board with her husband and one son, has said the family remained committed to L'Oréal and its management.