France led a minute's silence observed around the world on Monday in memory of the victims of the worst-ever terror attacks on French soil.

World leaders, diplomats and athletes joined with French expatriates, tourists and ordinary people around the world to mark Friday's violence which saw 129 people killed and hundreds more wounded.

In Paris, President Francois Hollande and his cabinet, all dressed in black, bowed their heads at the Sorbonne University, surrounded by scores of students.

At Place de la Republique near the site of many of the attacks, hundreds more stood still to remember those killed in the bloodbath, while large crowds also gathered in silence by the Bataclan music venue and outside a nearby bar and restaurant, where most of the victims died, AFP journalists said.

The seven EU leaders attending the G20 summit in Turkey -- David Cameron, Angela Merkel, Matteo Renzi, Mariano Rajoy, Laurent Fabius, Donald Tusk and Jean-Claude Juncker -- also observed the minute of silence in front of the main entrance.

In New York, hundreds gathered at the 9/11 Memorial, holding French flags and roses as they fell quiet.

French expatriates, tourists and Americans gathered at the "Survivor Tree" -- which was pulled from the wreckage of the World Trade Center, nursed back to health and replanted as a symbol of survival -- where they sang the French national anthem.

The United Nations Security Council also fell silent, with all 15 envoys rising to their feet to remember the victims, who came from 19 countries.

The England football team, due to play France in a friendly match on Tuesday, broke off training in Enfield, north of London, to pay tribute.

In front of London's majestic St Paul's Cathedral, tourists and passers-by stopped in their tracks to honour the dead as hundreds more paid their respects in Trafalgar Square. Union Jack flags flew at half-mast.

Some carried makeshift posters reading "Je Suis Paris" and "Stand up against Terrorism in the World", while a woman serenaded the crowd with Edith Piaf songs.

- 'Important to come together' -

Shortly after observing the tribute, NATO Secretary General Jens Stoltenberg, said the alliance stood "in strong solidarity with the government and the people of France in their unwavering determination to deal with the terrorist threat".

In Madrid, the scene of bombings that killed 191 people in March 2004, a hundred lawmakers paid tribute on the steps outside parliament as a nearby trumpeter played the Marseillaise.

At the city's Atocha station, where the 2004 bombings took place, about 50 people gathered, while some 300 others marked the event in front of City Hall.

A hundreds-strong crowd collected outside the French embassy in Berlin -- next to the Brandenburg Gate -- where thousands of bouquets have been left.

Hundreds also gathered in Amsterdam's historic Dam Square, while in The Hague, the Dutch flag flew at half-mast in front of parliament.

Young people paying their respects in Rome held hands and wept as a musician played "La Vie en Rose" on an accordion.

Moments of silence were also observed in Sweden, Norway and Denmark.

In Africa, almost 500 people observed the silence at the French school in the Democratic Republic of Congo's capital Kinshasa, while Ivory Coast 's Prime Minister Daniel Kablan Duncan and a dozen government ministers marked the event at the French embassy in Abidjan.

"This is a terrible tragedy," he said. "The French people are friends of Ivory Coast, and when your friends are in distress, you cannot help but feel their pain."

French embassies in Vienna, Prague, Havana, Kabul and Mexico City all observed the silence, as did the French schools in Ouagadougou and Rio de Janeiro.

"We decided to go with our children to show our solidarity with the city of Paris and the Parisians, it is a city that we love," said 37-year-old Pablo Libreros in Rio.

"It is important to come together and show we're not afraid."