This is the image that is trending on the #CharlieHebdo hashtag.

Thousands paid tribute to dead Muslim police officer Ahmed Merabet using the rallying cry 'JeSuisAhmed' after the heroic officer was gunned down in Paris.

Merabet was killed as he begged for his life by suspected Islamic fanatics, and the 'JeSuisCharlie' (I am Charlie) demonstrations that have swept the world in the wake of yesterday's shocking massacre paid tribute to him.

A huge manhunt for the two suspected gunmen in Wednesday's deadly attack on Charlie Hebdo magazine has entered its third day. French police are concentrating their search in a rural area of Picardy north-east of Paris where the two men reportedly robbed a petrol station.

The iconic Eiffel Power in Paris turned off its lights for five minutes on Thursday night to pay a sombre tribute to 12 people killed in the attack on the officers of French satirical weekly Charlie Hebdo.

The French landmark plunged into darkness around 8 pm (local time) as thousands of protesters gathered in the Republique Square for the second night. 

The metro stopped for a minute at midday and France paused briefly to remember those murdered; similar vigils were held worldwide.