Danish police have said three officers were shot and wounded at blasphemy debate in Copenhagen where the French ambassadorwas speaking.
Two gunmen are said to be still at large.
Reports say up to 40 shots were fired outside the venue in the Danish capital.
Controversial Swedish cartoonist Lars Vilks, who has drawn caricatures of the Prophet Muhammad, was also present at the debate.
Shortly after the attack, a message appeared on the Twitter feed of French ambassador Francois Zimeray saying he was unharmed.
The area around the venue, reportedly a cafe, is under lockdown, the BBC's Malcolm Brabant reports.
Police have erected cordons and are searching a nearby park, he adds.
Lars Vilks stoked controversy in 2007 by drawing pictures of the Prophet Muhammad dressed as a dog.