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The EU's top court ruled for the first time on the bloc's net neutrality rules Tuesday and confirmed that companies could not punish customers with a two-speed internet.

In its offers, Telenor, a major Hungarian internet provider, allowed customers one monthly gigabyte of high-speed internet after which the slowed down.

But in a special deals, Telenor exempted certain apps from the limit such as Facebook, Twitter and Messenger or music streaming services such as Spotify and Deezer.

The Hungarian regulator considered this to be illegal and banned the offer. Telenor launched a lawsuit and the competent in Budapest referred the dispute to the European Court of Justice.

The exemption was unfair, the European Court of Justice said in its landmark ruling, which will help set the standard on web offers by internet providers across Europe.

The Luxembourg-based court said that the aim of net neutrality is to ensure and free choice for users on the Internet.

However, with the special deal, Telenor hampered access to non-participating chat or music services.

"Such packages are liable to increase the use of the favoured applications and services and, accordingly, to reduce the use of the other applications and services available," a court statement said.