Hundreds of people queued from the early hours outside UK shops selling the latest edition of French satirical magazine Charlie Hebdo.
It comes as around 10 people have been arrested and questioned over the "possible logistical support" they may have provided three gunmen who carried out last week's attacks in Paris, Agence France-Presse reports.
Hundreds of mourners have turned out to pay tribute to murdered Charlie Hebdo cartoonist and editor-in-chief Stephane 'Charb' Charbonnier.
Charb was one of 12 people gunned down when brothers Chérif and Saïd Kouachi stormed into the satirical magazine's offices in Paris last week.
The tribute service was held in Pontoise, near Paris, as services to remember those killed in the attacks continue.
A total of 17 people were killed by the Kouachi brothers, working in conjunction with fellow gunman Amedy Coulibaly, went on a rampage in the city.
About 7,000 French Jewish people left the country last year and have moved to Israel because they did not feel safe.
The aunt of a man killed while trying to overpower gunman Amedy Coulibaly has told ITV News her family is fearful of their future in France.
A Muslim cleric in Pakistan has held a ceremony to honour Cherif and Said Kouachi, the two men suspected of the Charlie Hebdo massacre.