Apple was fined € 25 million (£ 21 million, $27 million) for deliberately slowing down older iPhone models without making them clear to consumers.
The fine was imposed by DGCCRF, France's competition and fraud watchdog, which said consumers had not been warned.
Apple confirmed in 2017 that it slowed down some iPhones, but said it did just that to "prolong the life" of the devices.
Apple said it resolved the issue with the watchdog in a statement, reported the BBC.
Why does Apple slow down old iPhones?
Many customers had long suspected that Apple slowed down older iPhones to encourage people to upgrade when a new one was released.
In 2017, the company confirmed that some models have been slowing down as they age but not to push people to upgrade.
It said that, as they aged over time, the lithium-ion batteries in the devices slowly lose their ability to supply peak performance which could lead to an unexpected shutdown of an iPhone to protect its electronic components.
So, it released a software update that "smoothed out" battery performance for the iPhone 6, iPhone 6s and iPhone SE.
After a customer shared performance tests on Reddit, the practice was confirmed, suggesting that their iPhone 6S had slowed significantly as it had aged. But had suddenly speeded up again after the battery had been replaced.
What did the regulator say?
The French agency told the BBC that iPhone users "were not informed that installing iOS updates (10.2.1 and 11.2) could slow down their devices".
As part of the agreement, Apple will be required to post a note for a month on its French- language website.
It says Apple "committed the crime of deceptive commercial practice by omission" and had agreed to pay the fine.
Does Apple still slow down older iPhones?
Yeah. Since the practice was confirmed by Apple in 2017, it has been implemented on several more iPhones including: iPhone 6, 6 Plus, 6S, 6S Plus, iPhone SE, iPhone 7 and 7 Plus, iPhone 8 and 8 Plus running iOS 12.1 or higher, iPhone X running iOS 12.1 or higher, iPhone XS, XS Max and XR running iOS 13.1 or higher.
The setting is only enabled when the battery begins to degrade, and iOS now offers clearer information to consumers about when performance management has been switched on.
"The effects of performance management on these newer models may be less noticeable due to their more advanced hardware and software design," Apple said.