A German newspaper which published three Charie Hebdo covers on its front page has been targeted by arsonists.
Hamburger Morgenpost is one of several German newspapers to republish Charlie Hebdo cartoons which feature depictions of the Prophet Muhammad.
At the time it said it was doing so out of solidarity with murdered French colleagues.
The day after the attack on Charlie Hebdo, which saw 12 people murdered, Hamburger Morgenpost published three front pages from Charlie Hebdo on its front page.
One featured Osama Bin Laden, one was the issue of the magazine from 2011 which included an apparent depiction of Muhammad and a speech bubble saying “100 lashes if you don’t die laughing” and one featured a Charlie Hebdo staffer kissing an apparently Muslim man under the heading “love is stronger than hate”.
Other German newspapers to publish Charlie Hebdo cartoons depicting Muhammad on their front pages included Berliner Kurier, BZ and Berliner Zeitung. Other newspapers to do so around the world include L”Echo in France and business newspaper Mint in India.
UK newspapers have so far declined to republish any Charlie Hebdo cartoons depicting Muhammad. The one exception is The Times which, the day after the massacre, published one small Charlie Hebdo Muhammad front on page four.
Hamburger Morgenpost said on its website that several files in its archive were destroyed in the overnight arson attack, but no-one was injured.
Hamburg police said two young men detained near the newspaper building were being held for questioning.
Several other German newspapersare now understood to be getting police protection.
Police spokeswoman Karina Sadowsky said several stones and a Molotov cocktail were found in the newspaper's archive in the basement of the building.
A spokesman for the Hamburg fire department said they were first alerted when the building's fire alarms went off, shortly after 2 am.
"We quickly managed to extinguish the fire," said spokesman Joern Bartsch.
German Interior Minister Thomas de Maiziere called on all citizens to be vigilant in their everyday lives in response to the attacks in France.