It added that French authorities had indicated there was no health risk from the products.
“The retailers are following the investigations carried out by suppliers with the greatest attention and waiting for the results of public inquiries,” it said.
The French probe aims to determine who supplied the horsemeat and whether the ready meal companies knew about the contamination.
If there is evidence that the firms knowingly mislead consumers, “we will not hesitate to take legal action”, French Consumer Affairs Minister Benoit Hamon told Le Parisien daily, external.
Early findings from the probe indicated that the horsemeat had been supplied since August, he added.
“We have estimated that the profits drawn from what seems to be a fraud lie around 300,000 euros (£253,000),” Mr Hamon said.
Preliminary results of the investigation are expected to be released on Wednesday.
Responding to the food scandal, the director of Findus France, Matthieu Lambeaux, said in a statement the company would file a legal complaint on Monday.
“We thought we had certified French beef in our products. But in reality, we were supplied with Romanian horsemeat. We have been deceived,” Mr Lambeaux said.