Polish supermarket chain Biedronka, a unit of Portugal's Jerónimo Martins, could be fined up to 10% of annual revenue, consumer watchdog UOKiK said, over an advertising campaign the regulator says was potentially misleading.
Poland's largest chain of discount stores offered to refund customers the difference if they found one of 150 products cheaper elsewhere as part of a promotion that ran from April to June.
However, UOKiK said that the regulations of the promotion made it much more difficult to receive the refund than advertising could lead consumers to believe.
"The rules seemed simple, the promise tempting, but the reality turned out to be different," the head of UOKiK Tomasz Chrostny said in a statement.
People wishing to take advantage of the promotion had to purchase the product in both stores, take photographs, submit an application online before receiving a code which they had to send by traditional mail, UOKiK said.
UOKiK also said that according to the regulations, consumers would not receive a refund of any price difference in cash, but instead would get a code that could be used in Biedronka stores.
It also criticised the fact that the regulations were not readily available in shops.
"We verified how the benefits resulting from the promotion were presented to customers and the rules of participation, and we came to the conclusion that the advertising messages could mislead consumers," Chrostny said.
In an emailed statement, Biedronka said it was 'committed to having the lowest prices on the market' and that its promotions were 'designed to create saving opportunities for Polish customers'.
'We are surprised with the information circulating in the media since as of now we didn't receive any formal correspondence from UOKiK,' the supermarket added.
No-one at UOKiK was immediately available to comment on the supermarket's statement.
In January of this year, the consumer watchdog imposed a fine of PLN 140 million (€30.7 million) on Kaufland Polska Markety over alleged unfair use of contractual advantage and mislabelling of vegetables.
UOKiK told Reuters in an e-mailed statement that a formal correspondence was sent to the company last week.