ATHENS, Greece - Masked youths attacked the French Institute in Athens with firebombs Friday, one of the sporadic acts of violence that still hit the capital almost daily since the police killing of a teenager nearly two weeks ago sparked the worst riots Greece has seen in decades.

The rage unleashed by the Dec. 6 shooting has lifted the lid on years of dissatisfaction over social inequality, poor employment prospects for young people and increasing anger with the conservative government's economic policies.

Friday's attack by about 20 masked men against the French Institute, a cultural and educational center, left windows smashed and a guard's booth burned, but the building's interior was not seriously damaged, police said. A nearby bank ATM was also damaged, but nobody was injured.

"Spark in Athens. Fire in Paris. Insurrection is coming," read one slogan spray-painted onto the building's walls in French. Another, written in Greek, read "France, Greece, uprising everywhere."

French Ambassador Christophe Farnaud, who visited institute, said French cultural institutions in Greece would be closed temporarily "as a precaution."

In western Athens, some 1,500 people held a peaceful protest against a separate shooting in which police say an unknown gunman shot a 16-year-old boy in the wrist late Wednesday.

"This is an answer to state repression," said one demonstrator, university student Dimitris Andriotis. "We will not stop coming out into the streets until our demands are met."

The protest march contrasted to the violence that broke out during a student demonstration by about 7,000 people in the center of Athens on Thursday. Around 200 masked youths hurled firebombs and chunks of marble at riot police, who responded with stun grenades and acrid tear gas.

By Friday morning, downtown Athens was calm, with crowds of Christmas shoppers out.

Greece's two largest trade union umbrella organizations had planned a rally to protest the government's 2009 budget, and professors were also to protest outside Parliament on education issues, but only a few people turned out for the protests.

Efstathios Anestis, spokesman of the GSEE trade union, said the demonstrators delivered a protest letter to the Parliament speaker voicing objections to the budget.

Separately, hundreds of students and youths gathered for a free concert in central Athens to support what organizers described as an uprising against state repression.

The two policemen involved in the shooting death of 15-year-old Alexandros Grigoropoulos have been jailed pending trial. One has been charged with murder and the other as an accomplice.

After two weeks of riots, a slogan spray-painted outside the Bank of Greece summed up the mood: "Merry crisis and a happy new fear."