France’s data protection agency been fined Google and Amazon for breaking the country’s rules on online advertising trackers known as cookies.

Google was fined €100 million while Amazon was hit with €35M fine, it is the largest fine ever issued by the French data privacy watchdog CNIL.

CNIL said Google and Amazon’s French websites had failed to seek visitors’ consent before advertising cookies were saved on their computers.

The regulator carried out investigations of the websites over the past year and found tracking cookies were automatically dropped when a user visited the domains in breach of the country’s Data Protection Act.

Under local French (and European) law, site users should have been clearly informed before the cookies were dropped and asked for their consent.

In Amazon’s case its French site displayed a banner informing arriving visitors that they agreed to its use of cookies. CNIL said this did not comply with transparency or consent requirements — since it was not clear to users that the tech giant was using cookies for ad tracking. Nor were users given the opportunity to consent.

CNIL has given the tech giants three months to change the information banners displayed on their websites or be fined a further 100,000 euros per day until the changes are made.

Google said: “We stand by our record of providing upfront information and clear controls, strong internal data governance, secure infrastructure, and above all, helpful products.

“Today’s decision under French ePrivacy laws overlooks these efforts and doesn’t account for the fact that French rules and regulatory guidance are uncertain and constantly evolving.”

Amazon said it disagreed with the CNIL decision, “We continuously update our privacy practices to ensure that we meet the evolving needs and expectations of customers and regulators and fully comply with all applicable laws in every country in which we operate,” it said in a statement.