"The Normans, the Huns, the Arabs, the great invasions after the fall of Rome have now been replaced by gangs of Chechens, Roma, Kosovars, Maghrebins and Africans who rob, assault and pillage," Zemmour declared in a radio broadcast in May last year.
"Excessive and shocking though these words may appear", the court declared in its judgement, they only referred to "a fraction of the communities and not to them in their entirety".
It dismissed charges of incitement to racial hatred and racial slander on these grounds.
Prosecutors had called for him to be fined 5,000 euros and for the radio station RTL to be fined 3,000 euros for posting the broadcast on its internet site.
Zemmour, who is much admired in hard-right circles, was found guilty of the same charges in 2011 for having said that "the majority of drug dealers are black and Arab, that's how it is, it's a fact" on national TV.
He also caused a row by appearing to call for the deportation of Muslims in a newspaper interview last year.
Far-right Front National leader Marine Le Pen has been ordered to stand trial in October on charges of inciting racial hatred after comparing Muslim street prayers to the Nazi occupation, legal sources said Tuesday.