Reuters –France's data protection regulator ordered Google to remove information from all versions of its website, not just in Europe, when it grants users' requests to scrub search results for their names under the so-called "right to be forgotten".
If the company does not comply in 15 days, the CNIL can open a sanctions process, it said in a statement on Friday.
The move ratchets up the pressure on Google a year after the European Court of Justice gave residents the ability to ask search engines to delete results that turn up under a search of their name when they were out of date, irrelevant or inflammatory.
Since then, Google and other search engines such as Microsoft's Bing and Yahoo have begun to grant de-listing requests when they meet certain criteria.
But there has been much debate over the implementation, especially of Google's decision to only scrub results from European sites, leading some people to appeal to local regulators.
The company maintains that it should only apply the ruling across its European domains, such as Google.fr in France and Google.de in Germany.
But EU data protection watchdogs, many legal experts and former German Justice Minister Sabine Leutheusser-Schnarrenberger, who has been among external experts advising Google on privacy following the European ruling, think it should be global.
Some individuals have taken Google to court to try to force a change. They include Dan Shefet, a French lawyer born in Denmark, who won a defamation case in French court recently that called for the global results to be scrubbed. Google has not complied.
"In accordance with the (European court) judgment, the CNIL considers that in order to be effective, de-listing must be carried out on all extensions of the search engine and that the service provided by Google search constitutes a single processing," the CNIL regulator said.
France is the first country to open a potential sanctions process against Google if it does not change its position on the scope of the de-listings. But the powers of the CNIL remain limited, since it can only impose fines of up to 150,000 euros.
The Mountain View, California-based Google had annual revenue of $66 billion last year.
Google was not immediately available for comment.