"An author of software cannot oppose the resale of his 'used' licences allowing the use of his programs downloaded from the internet."
This cannot be overrided by an End User's Licensing Agreement (EULA), either, whether sold on Steam, Origin, or any other digital distributor. "Even if the licence agreement prohibits a further transfer, the rightholder can no longer oppose the resale of that copy," the ruling clarified.
Gamers can sell their copies of their downloaded titles so long as they relinquish their rights to the game.
This will undoubtedly cause sweeping changes to videogame sales in the future, including the retail market. It'll be interesting to see how Steam and Electronic Arts in particular react to this ruling.
No such ruling has been made in North America, and it's doubtful the United States will adopt this ruling in the foreseeable future.