The European Union chief has hit back at a stinging attack that blamed the rise of the far right in Europe on the EU.
French industry minister Arnaud Montebourg said that ordinary Europeans felt alienated by the EU's policial paralysis and that had fuelled the growth of xenophobic groups across the continent.
European Commisson president José Barroso accused Montebourg of pointing the finger at the EU to deflect the spotlight from France's own troubles.
"Some French politicians would be better to give up any ambiguity towards Europe and defend it more instead against nationalism, populism and chauvinism," he said.
Montebourg told France Inter radio station: "The European Union is paralysed. It does not respond to people's aspirations in the industrial, economic or budgetary fields and in the end it provides a cause to all the anti-European parties," Montebourg told France Inter radio station.
"Mr Barroso is the fuel of the French National Front. He is the fuel of Beppe Grillo," he said. Grillo was a political outsider in Italy whose Five Stars Movement gained a quarter of the vote in February's general election.
Montebourg's comments followed the defeat of the Socialist party by the centre-right UMP in the Villeneuve-sur-Lot by-election. The seat, vacated by former minister Jerome Cahuzac, who was forced to resign amid tax fraud allegations, was won by Jean-Louis Costes in a close runoff vote with the far-right National Front contender Etienne Bousquet-Cassagn.
Relations between France and the EU have already tensed after Paris refused to discuss a review of its subsidies to its cinema and other cultural sectors.