French parents are not allowed to register their children in both their surnames. They have to choose one of them, which is inscribed on the birth certificate and becomes the child's name in law. The child may add a name when he reaches the age of majority, but it will always be an addition "by custom and usage", never recognised as part of the legal name.
So was an exception made for petit Martin Rey-Chirac, a French MP wanted to know, and he put down a written question to that effect in parliament. "Is this," asked Jean-Louis Masson, the honourable member for Moselle, only half tongue-in-cheek, "a favour exclusive to descendants of French presidents while in power, or is it a change in the law from which every citizen will be able to benefit from now on?"
Mr Masson's interest in the matter stemmed from the fact that he has spent more than a decade trying to change the law to allow a child to take both its parents' names. (He is the father of three daughters and no sons.) Suddenly, the law seemed to have been changed de facto by the president.
Claudia Chirac, Martin's mother, is the president's younger daughter and his trusted public relations adviser. The child's father - whose identity was disclosed to the French public only a couple of months before the birth - is Thierry Rey, who won a judo gold medal for France at the 1980 Moscow Olympics and is now a television presenter.
Although the French media referred to Claudia Chirac through her pregnancy as a "thoroughly modern woman" who decided to have a child "all by herself", Mr Rey was frequently photographed with Claude and is named as the father on the birth certificate.
The answer to Mr Masson's question has now been provided. Martin, it emerges, was not made an exception after all; he was registered only under his mother's name. Until he is 18, he is for legal purposes plain Martin Chirac.
The misapprehension, it is said, derived from a French media report which said he had been "registered" with the double-barrelled name. If it had simply said that he would be "known as" Martin Rey-Chirac, not an eyebrow would have been raised. Still, at least Mr Masson may benefit from all the fuss: next time he tries to have the law amended, he may get a more sympathetic reception than hitherto.