French antitrust authorities handed Apple a 150-million-euro ($162-million) fine on Monday over its app tracking privacy feature, which is also under scrutiny in several other European countries.

The watchdog said the way Apple implemented its App Tracking Transparency (ATT) software was "neither necessary nor proportionate to the company's stated goal to protect user data" and also penalized third-party publishers.

In addition to the fine, Apple will have to publish the decision on its website for seven days.

Authorities in Germany, Italy, Romania and Poland have opened similar probes over ATT, which Apple promotes as a privacy safeguard.

The feature, introduced by Apple in 2021, requires apps to obtain user consent through a pop-up window before tracking their activity across other apps and websites.

If they decline, the app loses access to the user's advertising identifier, which enables ad targeting. 

Critics have accused Apple of using the system to promote its own advertising services while restricting competitors.

In its decision, France's Competition Authority said the ATT feature leads to an excessive number of consent windows for third-party apps on iPhones and iPads, making the experience more cumbersome.

It also found that Apple's system required users to opt out of ad tracking twice rather than once, "undermining the neutrality of the feature" and causing economic harm to app publishers and ad services providers.

The authority added that Apple's approach disproportionately affects smaller publishers, who rely heavily on third-party data collection to fund their businesses.

Following complaints from advertising industry players who claimed ATT hindered their ability to target users, France's competition watchdog initially declined to impose emergency measures in 2021 but continued its investigation.