President Francois Hollande said he simply did not believe that European Commission head Jose Manuel Barroso could have made the comment over France's stance in free trade talks with the US.
His Culture Minister Aurelie Filippetti branded Barroso's remarks as "absolutely lamentable."
Barroso's unusually strong criticism came after France held up agreement on Friday between the EU's 27 trade ministers on the exact terms of the Commission's mandate to negotiate the EU-US free trade deal.
France, ever keen to protect its cherished film and culture sectors from Hollywood, insists that the audiovisual industry be excluded from the negotiations.
Without naming France, Barroso said in an interview Monday with the International Herald Tribune that those fearful of a US cultural invasion of Europe "have an anti-cultural agenda".
"Some say they belong to the left, but in fact they are culturally extremely reactionary," the president of the European Commission said.
EU officials have repeatedly warned that excluding any economic sector could hand the US an early bargaining chip in what promise to be tough negotiations.
Washington says no areas should be excluded from the talks.
President Hollande said as he arrived Monday at a G8 summit in Northern Ireland, where the long-awaited formal negotiations on the vast trade pact were launched, that he did not "believe that the president of the European Commission would have made such remarks".
Culture Minister Filippetti said in Paris: "They are unacceptable. Those who view France as reactionary would do well to remember that France is not alone in this fight.
"Our position is not defensive, it's not conservative and even less so reactionary. We will continue to mobilise and not let our guard down," she said.
Jean-Christophe Cambadelis, a national secretary from France's ruling Socialist party, said Barroso's remarks were "astounding and intolerable" and that he should "take back his comments or quit".
If the EU and the US finally reach an agreement, they will create the world's largest Free Trade Agreement (FTA).
Bilateral trade in goods last year was worth some 500 billion euros with another 280 billion euros in services and trillions in investment flows.
The EU says an FTA would add some 119 billion euros annually to the EU economy, and 95 billion euros for the United States.