A letter exploded Thursday at the French office of the
The incident came as a Greek anarchist group claimed responsibility for a failed letter bomb sent to the German Finance Ministry on Wednesday.
After Thursday's explosion in Paris, staff members at the IMF office were evacuated, and armed soldiers and police guarded the area, in a chic western district of the city.
It is unclear who sent the homemade explosive, which was like a "big firecracker" and sent by regular mail, said Paris Police Chief Michel Cadot. The IMF office had received threatening phone calls in recent days, but they were not necessarily linked to Thursday's incident, he said.
Hollande later said the government would do "everything to find out the origin of this malicious act".
He said the letter bomb bore "a similarity with another event of the same nature in Berlin."
"We are trying to establish the causes of what happened as part of an international investigation," Hollande said.
The secretary who opened the letter was injured in the face by shrapnel and hurt in the eardrum because of a "rather violent noise," the police chief said.
Police searched all four floors of the building, which also houses the World Bank office in France, Cadot said. No one else was injured, and the building incurred only light damage.
The Greek group that claimed responsibility for the failed German letter bomb, Conspiracy of the Cells of Fire, said in an online posting Thursday on a Greek left-wing website that the attempted attack was part of a concerted campaign by international anarchist groups.
Many Greeks resent austerity measures imposed by the IMF and the