Claims that Disneyland Paris is freezing out UK and German customers of certain price promotions could trigger a probe by Brussels.
People in the UK were paying 15% more for one-day tickets to the theme park near Paris, according to the Financial Times.
French consumers were in some cases paying €1,346 for a premium package, while UK visitors were charged €1,870 and Germans €2,447, the newspaper reported.
The European Commission told the BBC that it had “received a number of complaints” from customers.
A Disneyland Paris spokesman said promotions were seasonal.
The Commission is concerned that Disneyland Paris is stopping consumers in some member states from shopping around for the best deals, a spokeswoman told BBC Business Online.
Firms cannot stop consumers from doing this under European law, she said.
The problem potentially lies in a UK holidaymaker trying to order a Disneyland Paris ticket from a French website but being unable to pay because they do not have a French credit card.
The French government has now been asked to investigate.
A spokesman for Disneyland Paris said that the price of a standard ticket was the same across the European Union.
The firm runs different promotions at specific times of year based around, for example, seasonal events and school holidays.
Customers are not subject to so-called geo-blocking, where promotions are closed to those people whose computers are located in a certain country, the spokesman told the BBC.
But he added that customers would not be able to directly pay for tickets for a promotion for a certain country unless their credit or debit card is registered in that country.
“It’s an anti-fraud measure,” he said.
Stephanie Beckett, solicitor at Thomas Eggar LLP, said: “This is an issue of consumer discrimination and one that the Commission is alive to. Website blocking and IP identification are becoming common methods for companies to charge higher prices to consumers in different countries.
“A growing number of tour operators are selling holiday packages to more than one country, and tour operators and providers should be looking inwards at their own consumer practices to ensure that they are complying with the non-discrimination principle set out by in EU Directive 2006/123/EC.
“The Directive obliges services providers not to discriminate against consumers on grounds of nationality or place of residence, and tour operators which do so are likely to be contravening the rules of the EU single market.
“Any tour operators or tourist attractions using such pricing methods online, or elsewhere, face receiving complaints from consumers (particularly in light of the publicity surrounding this recent investigation) and being investigated by the Commission themselves.”