There is a political saying in France that the "extremes touch". Even in France, however, the extremes rarely shake hands in public.
The comprehensive triumph of Ségolène Royal in the Socialist presidential "primary" is not the only straw in the wind of a perplexing French electoral season. Mouths gaped last week when Jean-Marie Le Pen, veteran xenophobe and leader of the powerful French far right, chatted amiably in public with Dieudonné M'bala, a black comedian, one-time anti-racist campaigner, now the champion of a conspiracy-obsessed and anti-Semitic segment of the far left.
Dieudonné (always known by his stage name) turned up at the annual Red-White-Blue festival of Mr Le Pen's National Front at Le Bourget, allegedly on a whim and "just to have a look". It later emerged that the visit, and "chance" meeting between the two men, was planned by senior NF officials, with Mr Le Pen's and Dieudonné's knowledge, though the two men managed to avoid being photographed together.
What was going on? Dieudonné, 40, who has his own political comedy theatre in eastern Paris, has broken with many former friends on the left by insisting that all the ills of the world, and especially the problems of black people, can be traced to Israeli and Jewish influence. He was convicted earlier this year of making anti-Semitic statements.
Mr Le Pen, 78, was once a scarcely disguised anti-Semite and racist himself. Even last summer he was complaining that there were too many black faces in the France football squad at the World Cup. But he has tried to re-invent himself in recent months as a democratic nationalist and patriot, open to French people of all races and religions. Being seen with Dieudonné could help to enlarge his appeal in next spring's presidential election. The NF leader is convinced that he can repeat his stunning exploit of 2003 when he reached the two-candidate second round.
In the past couple of days, meanwhile, Dieudonné has said that he is "not the monster" people claim and that he has "every chance" of becoming the man who brings "political revolution" to France. The extremes may hate each other, but they also recognise a common enemy in Ms Royal.
But Mr Le Pen's National Front is riven by internal quarrels. Unreconstructed racists within the party jeered and insulted Dieudonné when he turned up at the NF festival, forcing him to leave early.
Mr Le Pen's own daughter, Marine, main architect of his recent lurch towards the middle ground, was also furious when she saw Dieudonné at the Le Bourget meeting. She had invited a militant Jewish protection group to come along to prove that the "nouveau" NF was not anti-Semitic.