The French regulator said that after investigations it found that "when users visited this site, cookies were deposited on their terminal without their consent, while these cookies were used, among others, for advertising purposes."
It also "observed that there was no button allowing to refuse the deposit of cookies as easily as accepting it."
The CNIL said the fine was justified in part because of the profits the company made from advertising profits indirectly generated from the data collected via cookies -- tiny data files that track online browsing.
The company has been given three months to rectify the issue, with a potential further penalty of 60,000 euros per day overdue.
Last year the CNIL said it would carry out a year of checks against sites not following the rules on using web cookies. Google and Facebook were sanctioned last year by the CNI with fines of 150 million and 60 millioneuros respectively for similar breaches.
Washington is demanding that the app’s Chinese owners sell their stake, company representatives have said