Ian Bailey has been arrested in Dublin in connection with the murder of Sophie Toscan du Plantier in West Cork in 1996.
His arrest comes after the High Court endorsed his extradition.
Sophie Toscan Du Plantier was beaten to death outside her holiday home in Schull in December 1996.
No one has ever been charged in connection with her murder.
Freelance Journalist Ian Bailey has consistently denied any involvement in her murder.
In May of this year he was convicted in absentia by a three judge court in Paris and sentenced to 25 years in prison.
Today the High Court endorsed his extradition to France and he was arrested by Gardai.