France's iconic Eiffel Tower was plunged into darkness late Thursday in a sombre tribute to the 12 people killed in the attack on the Paris satirical weekly Charlie Hebdo.
The lights normally illuminating the 324-metre (1,063-foot) tall monument at night were briefly turned off at 8:00pm (1900 GMT) before gradually coming back on.
The symbolic gesture came as thousands of people gathered on the other side of the city in Republique square to hold a second night of vigils in memory of the victims of the worst attack on French soil in decades.
"Our city has been a refuge for writers, philosophers, journalists who were threatened for their ideas," Paris mayor Anne Hidalgo told Liberation newspaper. "There is no place in Paris for extremist ideas of any sort."
The Eiffel Tower is one of France's top tourist attractions and the pre-eminent monument in the City of Light.
Earlier in the day, office workers stood shoulder to shoulder, buses and metro trains halted, and the toll of bells and the sound of weeping broke the silence in honour of the victims.
"Charlie will be free!" cried a woman joining a crowd in front of Paris' Notre Dame cathedral a moment before noon (local time) when the country observed a national minute of silence.
Among the hundreds gathered on the ancient square, many were in tears or stood with their eyes closed, while some prayed and a long line formed to enter the cathedral for a special memorial mass. "When you attack the press, you attack liberty," said Jean-Paul Doussin, an elderly man who removed his beret to show his respect, despite heavy rain. "You have to fight for freedom of expression." There was also tension, with large numbers of riot police moving through Paris in vans and camouflaged soldiers with automatic rifles on guard outside some government buildings.
But the main feeling in the capital was one of sadness. At the major rail station of Saint-Lazare, staff called on travellers and workers to pause at midday. "We must stick together and save our freedom of speech," said Julie, 37, who works for the national SNCF rail company.
The government has called for another round of even bigger demonstrations of nationwide solidarity on Sunday. Ten people at Charlie Hebdo -- including the chief editor and renowned cartoonists -- were gunned down on Wednesday by two men. Two policemen were also shot, one of them shot in the head at close range as he lay wounded on the sidewalk. Shocked politicians led by President Francois Hollande were seen on television taking part in the minute's silence. Islamic organisations from across France quickly sought to distance themselves from the jihadists and called on Muslims to join today's moment of silence and for imams to condemn terrorism at Friday prayers.
Twenty imams went a step further by appearing together outside the offices of Charlie Hebdo, along with hundreds of other people coming to express sympathy with the victims and to leave flowers.