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.
Senior religious leaders from Christian, Jewish and Muslim traditions joined forces to present a united condemnation of last week's terror attacks in France.
An interfaith "unity gathering" was held at the Islamic Cultural Centre at Regents Park Mosque in London, with around 20 prominent religious figures attending after the attacks, which left 17 people dead.
Dr Shuja Shafi, secretary general of the Muslim Council of Britain, told ITV News the massacre had "hurt and moved" everyone, and said the event had been organised to show such violence had "no place" in any faith.
He urged British Muslims to react with dignity after hundreds of copies of satirical magazine Charlie Hebdo, featuring a weeping Prophet Mohammed on the front, went on sale in the UK this morning.
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.