On Thursday, Google filed an appeal in France’s highest administrative court, continuing a years-long legal tug-of-war between the company and European lawmakers over the “right to be forgotten.”

What is the right to be forgotten?

The “right to be forgotten” burst into courtrooms in Europe with one Spanish man’s seemingly simple request in 2010: that notices from the 1990s announcing an auction of his repossessed house be taken down from Google Spain’s search results. His debts had been paid, but the embarrassing financial history appeared prominently in his search results. In 2014, the European Court of Justice agreed that Google Spain should stop indexing the man’s bankruptcy, effectively erasing his embarrassment from the internet unless someone really wanted to find it. (An important distinction is that the notices still exist online, but no longer appear in his search results in Europe.) The “right to be forgotten,” which this ruling enshrined, is someone’s right to digital privacy: to ask a search engine to scrub a search result that is “inadequate, irrelevant or no longer relevant” to the public interest. If the Spanish man had been a European version of Donald Trump, for example, he might not have had as broad of a claim to privacy.

Who gets to decide who has the right to be forgotten and who doesn’t?

The internet search engines (so, pretty much, Google) are in charge of determining which requests are honored. At Google, a committee of internet experts arbitrate the requests, deciding whether the public’s right to know a piece of information trumps the requestor’s right to privacy. So far, Google says it has approved 43 percent of all 1.5 million requested URL removals.

Where is the right to be forgotten enshrined in law?

After the European Court of Justice’s landmark decision, any European Union resident can use an online form to request that Google remove links for its search results. The European Union has had the most success in institutionalizing this principle, but Europeans aren’t the only ones who have had some success taking control of their search results. Citizens in countries including Mexico, Japan, and Argentina have also raised legal challenges about their “right to be forgotten” in Google’s searches, with varying degrees of success.

How does the forgetting work?

Currently, when Google upholds a European Union resident’s request to be forgotten, the requested link is removed from all of the European domains of Google, like Google.fr and Google.de. Google will also block the result in every other domain (including its global Google.com domain) if the person searching is located in the same country as the person who requested the removal, according to Google’s Europe Blog. That means that if a French resident requests that Google remove an embarrassing search item, anyone searching for that item from a France-based computer would be unable to view it no matter what version of Google he or she uses.

So what’s Google’s latest appeal about?

The French regulator CNIL fined Google 100,000 euros in March for failing to implement the right to be forgotten more broadly. It’s a small fine for a company that made $20.3 billion in revenue last quarter, but one that could have far-reaching repercussions.

According to Reuters, CNIL argues that the location of the searcher shouldn’t matter. People in the United States, for example, should not be able to see information about a European resident that has been “forgotten” in a search. Google’s appeal pushes back against the fine, arguing that the company could not uphold the right to be forgotten globally. In an op-ed published in Le Monde Thursday, Google’s global general counsel Kent Walker argued that CNIL’s preferred enforcement of the right to be forgotten violates a “foundational principle of international law.”

“We comply with the laws of the countries in which we operate. But if French law applies globally, how long will it be until other countries - perhaps less open and democratic - start demanding that their laws regulating information likewise have global reach? This order could lead to a global race to the bottom, harming access to information that is perfectly lawful to view in one’s own country.”

The appeal process is expected to take months.

Could the right to be forgotten ever come to the United States?

When the European Court of Justice ruled in favor of the right to be forgotten, many commentators said that ruling underlined critical differences in perspective between Europe and the United States. The United States generally has much stronger protections of free speech and the press than Europe. The First Amendment is one reason why it’s not likely the right to be forgotten would ever fly in the United States: a law forcing companies like Google to censor certain search results would probably be problematic in court.

But at least one (very weak) form of the right to be forgotten is starting to gain popularity. In California, minors have the right to request that websites delete content they posted online. But that law, which went into effect in 2015, falls far short of European law: it only allows teens to delete content they posted themselves, so embarrassing news items and pictures posted by friends are still out of reach.

Photos via Philippe Huguen / Getty Images

Claire Groden is a freelance writer living in Brooklyn. She has written for Fortune, Time, The New Republic, The Wall Street Journal, and others.

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