The apps we use every day to chat, shop, learn languages or just pass the time are often machines hungry for personal data. THE’investigation conducted by Que Choisir on 50 mobile applicationsboth iOS and Android, has revealed an alarming picture of our digital privacy.
The data business
Behind the apparent freeness of many apps lies an underground economy based on data brokers, companies specialized in the collection and resale of personal information. The mechanism is very invasive: developers install “trackers” in their appssmall software that recovers data from our smartphone and transmits it to external servers. This data is then aggregated to create detailed consumption profiles, resold to advertising networks.
The information collected reveals much more than we imagine: from our daily habits to the places we frequent, from culinary preferences to political interests. By cross-referencing this data with other profiles, brokers can even deduce who we spend time with and what kind of relationships we have.
The apps that steal the most data
The investigation identified some particularly problematic applicationsmany of which are among the most downloaded in the world. Among these stand out TikTokwhich collects an impressive amount of data for unclear purposes, Shein and Temu, Chinese e-commerce platforms that transmit huge flows of information to third parties, e BeReal, the seemingly harmless social network that actually shares user data massively.
An emblematic case then Duolingothe language learning app that takes over all your address book contacts – name, surname, email and phone number – without any apparent justification. Other problematic apps include Hi.AI for chats with virtual characters, VSCO and YouCam Perfect for photo editing, and even a simple PDF reader.
Out of 50 apps tested, 33 transmit large amounts of data. In some cases, information is sent in indecipherable formats, making it impossible to know exactly what personal data is being shared.
The few virtuous women who respect privacy
The investigation also identified 4 exemplary applications that keep their privacy promises: the strategy game Rift Riff (for both iOS and Android), the children’s piano game Happytouch and the Gifter app for gift management. These apps do not collect any data and require little to no permissions.
A second group of 13 apps behaves reasonably: they only request the permissions necessary to function and limit the sharing of data with third parties. These include Clash Royale, BayaM (children’s content from the Bayard group), Magic Pic and Xooloo Messenger Kids.
The test methodology
Que Choisir subjected the 50 apps to rigorous analysis. First step: verify that the data was encrypted and protected from external interception. Second: check the transparency of privacy information and the real possibility for users to oppose data collection. Third and most important: track all information flows between apps and external servers, distinguishing what is sent to developers from what ends up in the hands of third-party companies, identifying when possible which personal data is shared.
A transparency problem
The critical point, according to the investigation, is the lack of transparency. Users do not know what data is collected, where it is stored, how it is used and to whom it is resold. According to a study cited in the survey, in 2022, 80% of data collected by mobile apps was unrelated to their functionality.
An investigation by Le Monde in 2024 had already documented the extent of the phenomenon: in a single day, the broker DataStream Group had collected 380 million geographical coordinates from 47 million phones in 137 countries, through almost 40,000 applications. Apparently anonymous data which however allowed people to be easily identified.
As he points out Antoine Dubus, researcher at the Zurich Polytechnicthe issue goes beyond simple privacy: “The protection and control of our data determines the kind of society we want to live in”. An increasingly urgent reflection, as we continue to scroll absentmindedly at the screen, unaware of the price we are really paying to use it.
How to defend yourself
Que Choisir offers some practical advice to regain control of your data:
