An off-the-cuff remark by the Norwegian-born presidential candidate, Eva Joly, has plunged France into a four-day orgy of patriotic moralising and political name-calling.
Why, asked the official Green candidate, does France insist on celebrating its national day with a military parade? How can tanks and fighter bombers represent the republican values of liberty, equality and fraternity? Why not have a "citizens' parade" on Bastille Day instead, she argued?
Ms Joly's remarks initially provoked indignation from rival politicians of both right and left, who said her comments were insensitive as last Thursday's parade came the day after six French soldiers were killed in Afghanistan.
Then the centre-right Prime Minister, François Fillon, set off another political depth charge. He recalled that Ms Joly, 67, had come to France from Norway as an au pair in 1963. Her comments, he said, proved that she had "not been steeped for very long in French traditions, French values and French history". In other words, Ms Joly, the official Green-Europe Ecology candidate in next spring's election, was not truly French.
Cue another explosion of indignation from politicians of the left. Mr Fillon, normally a moderate and cautious man, was, they said, invading the xenophobic territory of the far right. To suggest that foreign-born French citizens were "unFrench" was to trample on French republican values.
The Socialist Party leader, and presidential candidate, Martine Aubry, said yesterday that if she was already President, she would have fired Mr Fillon for remarks which were "not clumsy, but shameful".
The row entered its fourth day yesterday, leading all news bulletins and newspapers. Other ministers came to Mr Fillon's defence and junior members of the governing centre-right party plunged into outright anti-Norwegianism. Lionel Tardy, a centre-right member of parliament, said: "It's time for Eva Joly to go back to Norway."
The virulence of the debate foreshadows an election campaign in which both President Nicolas Sarkozy and the far-right candidate, Marine Le Pen, are expected to raise issues of "identity", from immigration to "dual nationality".
Ms Joly was once a tenacious and much-feared investigating magistrate in France but is an inexperienced politician. She seemed to be stunned at first by the reaction to her off-the-cuff comment. She said yesterday that she was not "anti-military" and had the "most profound respect" for soldiers who risked their lives for France.