The attack is probably related to the ongoing riots in Tunisia, where 20 people were reportedly killed by the security forces.
Via AFP:
French police said a "small explosion" occurred at the Tunisian consulate in a Paris suburb early Sunday, which the country's ambassador denounced as a "terrorist act".
The blast took place around 5:00 am (0400 GMT) at Tunisia's office in Pantin and "caused minor damage to the consulate's metal shutters," said police, who have opened an investigation.
It could have been a petrol bomb that caused the explosion, local officials said.
Tunisia's ambassador to France, Raouf Najar, said in a statement sent to AFP: "The disinformation these past few days on what is happening in Tunisia is such that anything is possible, even this terrorist act."
(source)