European consumer authorities are investigating nine video game companies, including France’s Ubisoft, over concerns that their in-game virtual currencies might be violating users’ rights, the EU said on Wednesday.

The bloc is coordinating the investigations by the Consumer Protection Cooperation Network, which brings together the competent authorities of the EU’s 27 states.

The network launched talks with the companies last year, but the EU executive said the approach “did not bring satisfactory results”.

The European consumer authorities later identified several games that needed further study, including Candy Crush Saga, Minecraft and Clash of Clans.

The EU said that alongside Ubisoft, the other companies involved in the probe included Minecraft developer Mojang, US giant Riot Games, and Supercell, which makes Clash of Clans.

Authorities will now probe whether there are any breaches of EU consumer law.

The bloc’s guidelines on in-game virtual currencies say games must show the real-world price of any required in-game items and currencies. Games also must show clear information before any purchase, and companies must not force players into unwanted transactions.

Gamers should also be told they can withdraw from contracts within 14 days, including for unused virtual currency, the EU said.

“The industry must ensure that its games do not expose players — especially children — to harmful or unfair practices,” EU consumer protection chief Michael McGrath said. “The game must be fair, and the rules must be respected.”

He added in a statement: “National authorities, with the support of the Commission, will make sure they are enforced.”

The EU has also ramped up efforts to protect children online, announcing earlier this month rules that will force companies to make video games and social media platforms safe before minors use them.

The EU is also expected to unveil consumer protection rules known as the Digital Fairness Act that will cover the video game sector.