European consumer groups accused Thursday Chinese e-commerce retailer Temu of using "manipulative techniques" to force users to spend more and other violations of a landmark EU tech law.

One of the fastest-growing apps, Temu only entered the EU market in April 2023 and says it has, on average, around 75 million monthly active users in the 27-country bloc.

Europe's BEUC umbrella consumer rights group filed a complaint with the European Commission, while 17 member organizations in Europe, including France, Germany and Spain, have done the same with national authorities.

The groups accuse Temu of "failing to protect consumers and for using manipulative practices which are illegal," known as dark patterns, and demanded an investigation.

They believe Temu is distorting or impairing consumers' ability to make "free and informed decisions" while shopping online, in violation of the EU's mammoth online content law, known as the Digital Services Act (DSA).

Under the DSA, all digital platforms must remove illegal content quickly, be more transparent about how they use users' data and ensure the safety of shoppers online.

The platform fails to provide enough information about traders on Temu, "frequently leaving consumers in the dark about who they purchase products from," BEUC said.

And there is not enough information about how its "opaque" recommendation system works, it added, which is mandatory under the DSA.

Temu, owned by China's PDD Holdings, has already come under pressure in Europe.

German consumer groups warned Temu earlier this year about similar issues, which led to the platform announcing it would no longer display notices telling consumers to "Hurry up! Over 126 people have this item in their shopping cart."

It has faced fierce scrutiny elsewhere, including in Asia and the United States.

South Korean regulators in April began investigating Temu on suspicion of false advertising and unfair practices.

The EU is expected to add Temu to its list of "very large" digital platforms under the DSA, which will force the company to comply with stricter rules, including providing regular information about how it is mitigating risks.

Brussels has already added Chinese-founded online retailer Shein to its list, which also includes AliExpress, Amazon, Facebook, Instagram and YouTube, among 23 other platforms.