A summit of European Union leaders is threatened to be overshadowed by a row over France's expulsions of gypsy communities to poorer parts of Europe.
On Tuesday, EU Justice Commissioner Viviane Reding called France's handling of the deportations a "disgrace" that could breach European law and compared them to Second World War-era mass expulsions.
French government spokesman Luc Chatel hit back, saying: "It is unacceptable to compare the situation today with a tragic period in our history. I fear that such positions... will only widen the gap between the French people and the European institutions."
The war of words will make for an uneasy trip to Brussels for French President Nicolas Sarkozy, a dominant and outspoken figure at EU leaders' meetings and on the global stage.
The expulsions of gypsies, also known as Roma, from France, primarily to Romania, have highlighted persistent divisions between richer, older EU members and poorer, newer ones - and revived memories of historic hostilities in Europe that the bloc was meant to overcome.
The French government says the issue of the Roma isn't on the agenda at the summit, which is aimed at producing a more unified foreign policy, and a senior official added that "as far as we know, nobody intends to raise it".
But EU Commission President Jose Manuel Barroso said France and the EU should use the summit as "a moment for dialogue", raising hopes he would bring up the issue on the sidelines of the one-day summit.
Mr Barroso said he stood steadfastly behind Ms Reding's comments, saying her surprisingly blunt criticism of Paris was made "with my personal backing". But he added that "expressions used in the heat of the moment may have given rise to misunderstandings".
EU President Herman van Rompuy called Thursday's summit to discuss how the bloc communicates and what its strategic goals are with key countries such as the United States and China. Mr Van Rompuy will also update the leaders on progress by a taskforce on economic governance.
Mr Van Rompuy says the 27-nation bloc, which accounts for 22% of the world's economy, is "punching below its weight" and wants leaders to discuss how they can build a common foreign policy message and "deliver it effectively".