French President Nicolas Sarkozy has described comments by an EU commissioner about Roma deportations from France as "outrageous".
EU Justice Commissioner Viviane Reding appeared to compare France's actions to persecutions in Nazi-occupied France.
"The disgusting and shameful words that were used - World War II, the evocation of the Jews - was something that shocked us deeply," Mr Sarkozy said.
France would continue to dismantle Roma camps, he added.
"I am the French president and I cannot allow my country to be insulted," Mr Sarkozy told a news conference at an EU summit in Brussels.
He also confirmed he had had a heated exchange with the European Commission President, Jose Manuel Barroso, on the subject of Roma deportations.
The BBC's Oana Lungescu, who is at the summit, says this is an unprecedented row between Brussels and Paris.
Mr Barroso recognised that some excessive comments had been made, but insisted that discrimination against ethnic minorities was unacceptable.
"It is true that in the past few weeks, some things have been said that are out of order," Mr Barroso admitted. "But I think we need to leave that on one side now."
Ms Reding, the EU commissioner from Luxembourg, said on Tuesday: "This is a situation I had thought Europe would not have to witness again after the Second World War."
She also urged the European Commission to take legal action against France over the deportations.
Ms Reding later said she regretted interpretations of her statement.
Although France has deported thousands of Romanian and Bulgarian Roma over the past few years, it began accelerating the process last month, as part of a high-profile crackdown on illegal camps in the country.
On Monday, Euro MPs accused the commission of failing to protect the Roma deported from France.
In all, Mr Sarkozy said around 500 camps were dismantled in August, of which 199 were Roma settlements.
About 5,400 people were evicted from the Roma camps, but the majority of those living in the camps were French nationals, the president said.
The president's assertions appeared to contradict a leaked memo from the French interior ministry which surfaced on Monday.
It showed the authorities had been instructed to target Roma camps, rather than deal with migrants on a case-by-case basis, as the French migration minister and the minister for Europe had assured the European Commission.