The New York Times reports that French authorities are investigating "up to 100 people" (including the comedian Dieudonné M'bala M'bala, who was arrested on Wednesday) for "making or posting comments that support or try to justify terrorism." Yes, that is a crime in France, where "publicly condoning" terrorism can get you five years in prison and a €75,000 fine. If you do it online, the maximum penalty rises to seven years in prison and a €100,000 fine. Pro-terrorism speech was criminalized in November, but the law was not enforced until after last week's attacks on Charlie Hebdo and a kosher market in Paris.

Condoning terrorism is distinct from inciting terrorism, which involves directly encouraging people to commit acts of violence. All that is necessary to be guilty of this new crime is to speak approvingly of terrorism. Dieudonné, for example, wrote this on Facebook after last week's attacks: "Tonight, as far as I'm concerned, I feel like Charlie Coulibaly." He is scheduled to be tried next month, and presumably the only question will be whether he meant to condone terrorism when he combined the name of the newspaper that was attacked with the name of the man who murdered four people at the market.

In other cases there is less ambiguity. The Times says "a 28-year-old man of French-Tunisian background" got six months in jail for shouting this as he passed a police station in Bourgoin-Jalieu: "They killed Charlie, and I had a good laugh. In the past they killed Bin Laden, Saddam Hussein, Mohammed Merah, and many brothers. If I didn't have a father or mother, I would train in Syria." The Times also notes that "a 34-year-old man who on Saturday hit a car while drunk, injured the other driver and subsequently praised the acts of the gunmen when the police detained him was sentenced Monday to four years in prison." According to Le Monde, the drunk driver allegedly said, "There should be more of Kouachi [the Charlie Hebdo gunman]. I hope you will be the next….You 're a godsend for terrorists."

It's not clear how much of that four-year sentence was for the drunken remarks, as opposed to the drunken driving. Le Monde reports that "the glorification of terrorism was…an aggravating circumstance: he refused to submit to a breathalyzer test, was re-offending and the accident caused unintentional injuries." The paper, which counted 69 criminal investigations involving approval of terrorism as of Wednesday, also cites a case in which a man got a one-year sentence for shouting, "I am proud to be a Muslim. I do not like Charlie. They were right to do that." A 21-year-old man got 10 months for saying at a train station, "The Kouachi brothers is just the beginning. I should be with them to kill more people."

The fact that people have already been sentenced for speech crimes committed last week shows how determined French officials are to squelch expressions of support for terrorism by ramming these cases through. The Times notes that "the criminal justice system [has been] greatly accelerated, moving from accusations to trial and imprisonment in as little as three days." On Wednesday the Ministry of Justice urged prosecutors to target "words or acts of hatred" with "utmost vigor."

Prosecutions like these would never pass constitutional muster in the United States. In the 1969 case Brandenburg v. Ohio, which involved a Ku Klux Klan leader who advocated terrorism, the Supreme Court said such speech can be be punished only when it is directed at inciting "imminent lawless action" and is likely to do so. "They were right to do that" and "I feel like Charlie Coulibaly" clearly do not meet that test.

The ban on condoning terrorism is just one of many restrictions on speech in France that would be barred by the First Amendment if attempted in the United States. It is also a crime in France, for example, to insult or defame people based on their race, religion, ethnicity, national origin, sex, sexual orientation, or disability; to incite hatred, discrimination, or violence based on those criteria; to deny the Holocaust or defend war crimes; and to insult the head of state. As Le Monde explains, "freedom of expression is an absolute principle in France," but "it can be regulated." A lot. So when the French government says, as it did after the Charlie Hebdo massacre, that "artistic freedom and freedom of expression stand firm and unflinching at the heart of our common European values," that should not be interpreted to mean that people cannot be sent to prison for saying offensive things.

The many exceptions to freedom of speech in France lend weight to complaints that the government is quick to arrest Muslims for seeming to condone terrorism (or for making anti-Semitic jokes) but gives a pass to material, such as Charlie Hebdo's Muhammad cartoons, that offends Muslims. Alexander Stille tries to explain this apparent double standard in a recent New Yorker essay. "You can ridicule the prophet," he writes, "but you cannot incite hatred toward his followers." That is why a legal challenge to the Muhammad cartoons failed, Stille says, but Brigitte Bardot was convicted for saying, with reference to French Muslims, "We are tired of being led around by the nose by this population that is destroying our country." Stille suggests that the distinction between attacking ideas and attacking people also explains why the novelist Michel Houellebecq was not punished for calling Islam "the stupidest religion."

This explanation is not very convincing, since it is a crime in France not only to incite hatred but merely to insult individuals or groups based on their religion, and what counts as an insult is highly subjective. Judges disagreed, for example, about whether the Jyllands-Posten cartoon showing Muhammad wearing a turban shaped like a bomb should be considered an attack on Muslims in general or merely on Muslim extremists. The more you delve into the reasoning of these decisions, the clearer the fuzziness becomes.

"These kinds of exceptions, selective restrictions, and ambiguities in France's freedom-of-expression laws have left the country vulnerable to charges of political favoritism," Stille writes. "France might consider either a broader conception of free speech—the notion that the answer to bad speech is more speech—or doing a better job of clarifying what is allowed, and why." The latter option seems hopeless, because distinguishing between tolerable and intolerable offensiveness is inherently subjective. In addition to violating freedom of speech, these restrictions undermine the rule of law because it is so hard to predict which words will make you a criminal.