Two conflicting sides on whether there should be limits to the liberty of self-expression clashed violently Wednesday in a usually tranquil side street on the Right Bank of Paris.
When it was over, a dozen people lay dead --including some of the most prominent political cartoonists and satirists in France, and the police officers assigned to protect them.
Paris Mayor Anne Hidalgo mourned the slain as "martyrs of freedom, of freedom of the press, the pillar of democracy," and called upon all freedom-loving people to hold a solemn march in their memory Thursday.
On the other side of the Atlantic, President Barack Obama denounced an attack on the "values that we share with the French people -- a universal belief in the freedom of expression."
"The fact that this was an attack on journalists, attack on our free press, also underscores the degree to which these terrorists fear freedom of speech and freedom of the press," Obama said.
The slayings at the French satirical publication Charlie Hebdo were celebrated in some parts of the world because it was deemed to have outrageously and repeatedly abused its freedom to mock and shock.
A member of the Al-Qaida in Yemen extremist organization, posting on the Twitter social network, accused the weekly of engaging in the "defamation of Islam." As news of the killings in Paris reached the Middle East, celebratory gunfire was reported in a Palestinian refugee camp in southern Lebanon.
Almost immediately, there seemed little if any doubt about the motive behind what was termed France's deadliest terrorist attack since 1945. On video filmed by eyewitnesses, the gunmen can clearly be heard to shout the traditional Muslim exhortation "Allahu Akbar!" -- "God is great!" -- outside the newspaper's offices.
"We have avenged the prophet!" the men shouted as they fled, police sources told French media.
Though atypical in the size of its human toll, the attack in the Rue Nicolas Appert seemed the latest chapter in a clash of values between the West and a version of militant Islam that is at least a quarter-century old, beginning when Ayatollah Khomeini, Iran's supreme leader, issued a 1989 fatwa calling for the assassination of novelist Salman Rushdie, accused by some conservative Muslims of blasphemy.
Press freedom, and self-expression in general, differs vastly in the world, with even a liberal country like Sweden possessing laws that criminalize what's considered hate speech and prohibiting expressions of contempt directed against a group or one of its members.
In some nations, such as North Korea, the media are an arm of the state, or, as in Russia, have largely been transformed into a government mouthpiece. But the Paris attack was so horrific that even President Vladimir Putin, who has done much to muzzle his critics in the Russian media, called it a crime.
Not always to the liking of French government authorities, who endeavor to maintain good relations with the Arab and Muslim worlds, the clash over what limits to place on press freedom has often involved Charlie Hebdo, whose mix of crude, often obscene artwork and brash political satire has few if any parallels in Anglo-Saxon media.
In 2006, the left-leaning, iconoclastic tabloid, which regularly skewers a wide range of targets from the Vatican to Hollywood, reprinted 12 cartoons of the Prophet Muhammad whose original publication by a Danish newspaper touched off riots in some Muslim nations. Some Muslims were outraged that their religion's founder was being mocked, or even depicted at all.
Five years later, after Charlie Hebdo published a spoof issue supposedly guest-edited by Muhammad, its offices were firebombed and its website hacked.
The publication has been sued by several French Muslim organizations, accused of publishing racist cartoons, but won acquittal. In 2012, French police detained a man suspecting of threatening to decapitate the editor-in-chief.
This week, the publication's front page featured one of France's most controversial writers, Michel Houellebecq, whose latest book paints a worrisome picture of France in a not-too-distant future after an Islamic government takes power.
Also in the latest edition, Charlie Hebdo editor Stephane Charbonnier contributed the caricature of what clearly is meant to be a Muslim extremist_a bearded man with a Kalashnikov and an Afghan-style hat_hinting at a terrorist attack sometime this month in France in the guise of New Year greetings.
Charbonnier, whose pen name was "Charb," was one of those killed on Wednesday. In 2012, speaking to The Associated Press, he defended his magazine's right under France's laws safeguarding the freedom of expression to print crude, lewd caricatures of Islam's founder.
If some people didn't like it, Charb said, that was too bad.
"Muhammad isn't sacred to me," he said. "I don't blame Muslims for not laughing at our drawings. I live under French law. I don't live under Quranic law."
At that time, though, the French government, as well as the White House, openly questioned not the magazine's right to print, but its good judgment. At least 30 people had already been killed in violent protests over an amateur U.S anti-Islam video that portrayed the religion's founder as a fraud, womanizer and child molester.
"Is it pertinent, intelligent in this context to pour oil on the fire?" French Foreign Minister Laurent Fabius asked then. "The answer is no."
In the wake of Wednesday's shocking bloodbath, such calls for editorial restraint vanished. French President Francois Hollande, speaking outside Charlie Hebdo's office, said the gunmen had targeted journalists striving to "defend their ideas, and to defend precisely the freedom that the (French) Republic protects."
"We are threatened because we are a country of liberty," Hollande said, asking for national unity.
Rushdie, who spent years in hiding for fear of Islamic death squads, said Wednesday the conflict in the case of Charlie Hebdo was a stark and irreconcilable one, between the art of satire as a "force for liberty" on the one hand, and "tyranny, dishonesty and stupidity" on the other.
Dahlburg reported from Brussels. Associated Press writers Jon Gambrell and Sarah El Deeb contributed from Cairo.