Dutch regulators have fined KPN and Vodafone for breaching net neutrality rules.
The Netherlands Authority for Consumers and Markets (ACM) announced it had imposed fines of €250,000 on KPN and €200,000 on Vodafone.
KPN is charged with blocking various services, including several internet calling services, on its free Wi-Fi hotspots.
Vodafone offered plans with which customers were able to watch pay-TV channel HBO using an app without charging these customers the data used for watching the channel.
The ACM said Vodafone had influenced its customers’ online behaviour, which is not allowed.
The Netherlands became the first country in Europe, and the second in the world, to enshrine net neutrality in law in 2012.
Henk Don, Member of the Board of ACM, commented: “Internet providers are not allowed to decide for consumers what they can do on the Internet, and they are not allowed to influence their behaviour either.
“All data must be transmitted under the same conditions. That is the idea behind net neutrality, and that is what we are enforcing in these cases. ACM thus prevents consumers from having less freedom of choice online.”
KPN and Vodafone were not immediately available for comment.
Net neutrality proposals are at the heart of proposed reform of the wider European telecoms market, which Brussels wants to push through this year.
Last November, Swisscom, Sunrise, Orange and upc cablecom signed a net neutrality agreement that they claimed would guarantee an open internet in Switzerland.
In the UK, EE, Virgin Media and Vodafone signed up to the Open Internet Code last week.