Paris, Jan 11 (AFP): More than 700,000 people today took to streets across France in tribute to the 17 people killed in three days of violence by Islamist extremists, the interior minister said.

From Nice and Marseilles in the south to Besancon in the east and Lille in the north, people poured onto the streets to express their solidarity following Wednesday's attack on the satirical weekly Charlie Hebdo that left 12 dead.

The massacre was followed by the fatal shooting of a police officer on Thursday and the murder of four hostages during a siege at a Jewish supermarket yesterday.

"700,000 people have marched" in cities around France, Bernard Cazeneuve told reporters on the eve of a huge Paris rally planned due to be attended by a string of world leaders.

Cazeneuve did not give a detailed breakdown of the figure, but according to an AFP tally of demonstrations many thousands turned out across the country.

In the southern city of Toulouse, police said around 80,000 people took part in a march, with the "enormous" procession stretching up to two kilometres, according to an AFP journalist.

"Live together, free, equal and in solidarity," read the banner behind which at least 30,000 people also marched in the western city of Nantes.

In Marseille, 45,000 people expressed similar sentiments with a rally banner that said "For democracy, equality, freedom, let's fight fascism". Individual marchers held up placards with the words "Not Afraid!"

In Pau, a further 30,000 to 40,000 people staged a silent march with school pupils leading the way holding a banner emblazoned with the words: "We are all Charlie".

"It's a great popular movement... it's beautiful and significant, infinitely precious," the southwestern city's mayor Francois Bayrou told AFP.

In Besancon, another 20,000 took to the streets, an AFP correspondent said, while in northern Orleans around 22,000 rallied, according to a police source.

In Nice, at least 23,000 demonstrators were counted, police sources said, in a demonstration which snaked for around a kilometre along the famous seafront Promenade des Anglais, ending at the war memorial where a wreath was laid in the presence of representatives of different faiths.

A further 22,000 people turned out in northern Lille and thousands more in several other towns and cities across France.