As news of the attack on the Parisian kosher supermarket broke last week, social media was flooded with messages of support for the victims.
World leaders, communal organisations and ordinary people followed the JC in spreading the "Je Suis Juif" ("I am Jewish") hashtag, echoing the "Je Suis Charlie" and "Je Suis Ahmed" call after the attack on the French magazine offices in which Muslim policeman Ahmed Merabet was killed. #JeSuisJuif has been tweeted more than 20,000 times.
Profile pictures on Facebook were quickly replaced by the "Je Suis Juif" placard, with white letters against a black background. They were also held up by people at the solidarity rally in Trafalgar Square on Sunday.
At the march in Paris, UK Prime Minister David Cameron said that he was most moved by a placard that read: "Je Suis Charlie, Je Suis Flic [I am police officer] et Je Suis Juif."
However, Israeli Prime Minister Benjamin Netanyahu's presence in Paris prompted a flurry of condemnation on social media.
Critics of Israel tweeted hashtags such as #JeSuisGaza. Liberal Democrat MP David Ward tweeted: "Netanyahu in Paris march - makes me feel sick. Je suis Palestinian".
BBC TV reporter Tim Willcox tweeted an apology after coming under fire for having said to a Jewish woman live on air: "Many critics of Israel's policy would suggest that the Palestinians suffer hugely at Jewish hands." He said on Twitter that it had been "a poorly phrased question - it was entirely unintentional".
A BBC spokesman would not reveal complaints figures "when there is evidence of coordinated lobbying".
The International Business Times, removed an online article which implied that Mossad agents had been behind the attack on Charlie Hebdo, in response to French MPs voting in favour of recognising a Palestinian state.
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