'Nothing' the same after attacks, Paris mayor says

"Nothing will ever be as before", Paris Mayor Anne Hidalgo said Tuesday as her New York counterpart paid an express visit of solidarity to the French capital recently hit by jihadist attacks.

"We will not be able to pretend like it didn't happen," Hidalgo told reporters, as she stood next to Bill de Blasio in a cafe on the Place de la Republique, where hundreds of thousands gathered more than a week ago in memory of the 17 people killed during the violence.

"We must diagnose... why we got to this, what didn't work in what we did," she said, calling "for a bit more kindness in relationships that we have with each other in this society."

"In the Republican motto, there is liberty, equality, fraternity. Often we forget fraternity." De Blasio said Paris and New York had "walked the same path in so many ways", most notably because they were both victims of terrorist attacks.

He visited a memorial site outside the Charlie Hebdo magazine offices - where prominent cartoonists among others were mowed down on January 7 - and the Jewish supermarket where four people were killed during the attacks that ended on January 9.

"Seeing where people lost their lives because of who they were and what they thought, because they happened to be Jewish, because they were devoted to their faith or because they happened to believe in freedom of speech, is a reminder that these values are always under threat," he said.