PARIS — The brazen terrorist attack against the French satirical weekly magazine Charlie Hebdo that left at least 12 dead Wednesday has shocked the nation and the world. But it doesn't come in a vacuum, following a series of attacks in the past few years that have no parallel in any other Western country.

There are cultural and historical explanations for why France has long had to struggle against extremist violence, but the recent uptick is notable relative to other European countries facing similar situations.

There is no fixed pattern, and the attacks include both lone-wolf criminals and those with links to organized terror groups, and indeed a previous attack on Charlie Hebdo for its depiction of Islam.

December 2014: On Dec. 20, Bertrand Nzohabonayo, 20, attempted to stab several police officers in a precinct in the small French town of Joué-lès-Tours. The young man, who was believed to have shouted "Allahu Akbar" ("God is great") during the incident, was shot dead by police. He converted to Islam four years earlier but was not known by his relatives or French intelligence to have had any radical activities. Three days before the attack, however, the man allegedly posted several photos of the ISIS flag online.

Two days later, on Dec. 22, a man drove a car into 11 people in the city of Dijon while also reportedly shouting "Allahu Akbar." None of the victims died but two were seriously injured. Authorities raised doubts about the terrorist aspect of the attack, because it was later reported that the man was mentally ill. But several testimonies reported he shouted "in the name of the children of Palestine."

July 2014: On July 13, a synagogue in central Paris was attacked with Molotov cocktails following a pro-Palestine demonstration. Several altercations had already erupted during the day, but the demonstration was mainly peaceful. There were then clashes between several pro-Palestine protestors and members of the Jewish Defense League, which the French government regards as a terrorist organization. No victims were reported.

May 2014: On May 24, an armed man entered the Jewish Museum in Brussels, Belgium, killing four people. The suspected terrorist is Mehdi Nemmouche, a French-Algerian radical Islamist believed to have been sent from Syria by ISIS to strike Europe. According to a French police investigation, Nemmouche had also planned to commit a terrorist attack in Paris on July 14, during the national holiday parade. He was arrested in Marseille, in the south of France, on May 30, before being extradited to Belgium in July.

The funeral of the Jewish couple killed during the attack on the Brussels Jewish Museum in May 2014 — Gil Cohen Magen/Xinhua/ZUMA

November 2013: On Nov. 15, Abdelhakim Dekhar, 48, entered the Parisian offices of the French television station BFM-TV and threatened the editor before leaving the scene. He then went to the daily Libération, where he shot a young photographer in the hallway. The victim later died. After fleeing the scene once again, he fired shots on a bank in the financial district of the French capital after having briefly taken a driver hostage. He was later arrested in an underground car park in a neighboring town. Dekhar's motives have never been clear, but in letters written before the attacks, he talked about the Lybian and Syrian conflicts as well as the "fascist plot."

March 2012: On March 11 and 15, Mohamed Merah, 23, shot and killed three French soldiers, in the southern cities of Toulouse and Montauban. A few days later, on March 19, he killed three children and a teacher in a Jewish school in Toulouse. He was killed during an intervention by French special operations forces on March 22, following a 32-hour siege of his apartment. Merah was reported to be a French-Algerian who turned to radical Islam a few years earlier while in prison.

After the raid that killed Mohamed Merah in Toulouse, southern France, in March 2012 — Ki Price/ZUMA

November 2011: Wednesday's deadly attack on Charlie Hebdo is not the first time the magazine has been targeted for exercising its right to freedom of speech. On Nov. 2, 2011, the offices of the satirical newspaper in Paris were burned down after a Molotov cocktail was thrown inside. Charlie Hebdo had just published an edition titled "Charia Hebdo" ("Islamic Law Hebdo") in reaction to the rise of extreme Islamism in Libya and Tunisia.