Good dogs are the sort that were on parade last weekend in glorious summer weather on the Longchamps racecourse. The French national dog show is a infinitely more relaxed occasion than its British equivalent, Crufts, which may have something to do with its being held outdoors in summer, not indoors in winter. There is the same manic grooming of claws and fur at the last minute and the same deadly rivalry between the owners of champions. But there is a great deal more space for "walkies" in between times, a ramshackle spontaneity that has the standard poodles running round the show ring in less than perfect formation (at Crufts they look as though they have been in circus training since puppyhood), and a flick of Gallic irony that means that none of it is taken too seriously.
There is, moreover, a recognition that those attending a dog show may well have dogs of their own and will not want to leave them at home. Beasts of distinctly questionable pedigree are thus to be seen walking nonchalantly among the show dogs, lending an air of egalite to proceedings.
It also gives rise to announcements such as this: "Mesdames et messieurs, in view of the exceptionally high temperature, you should not have left your dog in a closed car. You should take your dog out at once. Where any dog seems to be showing signs of distress, the car windows will be smashed." Good dogs, with pedigree or without, are looked after.
Bad dogs, on the other hand, are a nuisance and are finding themselves increasingly unwelcome in "nice" society. The French eye distinguishes good and bad dogs instantaneously. Bad dogs are usually big, shaggy in an unkempt way and restrained, if at all, on lengths of dirty string. Invariably, these bad dogs hunt in packs, come from out of town and are accompanied by groups of 10 or so young to middle-aged individuals of similar appearance who engage in the practice described by the Labour MP Jack Straw as "aggressive begging".
In recent years, such groups have taken to settling - eating, sleeping and generally living - on the main squares and thoroughfares of some of France's choicer towns and cities, especially in the south. This time last year, the mayors of Nice, Toulouse, La Rochelle and other cities, worried that their behaviour was driving away tourists, passed by-laws against begging. No legal language was adequate, however, to distinguish between old-fashioned tramps, who had been tolerated with a degree of affection, and the new-style able-bodied sunseekers. The by-laws were declared unconstitutional.
This year, the same mayors are targeting new by-laws against uncontrolled, unidentified dogs. The hope is that if "bad" dogs are banned, the undesirable humans accompanying them will go too. It is too early to say whether this will happen, but a legal battle over the degree of constitutional protection accorded to dogs, good or bad, cannot be ruled out.
The "dangerous dog" is a recent addition to France's canine categories and comprises a single variety of dog: the pitbull. Any constitutional rights the pitbull might have enjoyed are rapidly shrinking. By-laws requiring them to wear muzzles are proliferating, and the equivalent of the Special Branch is compiling a register of pitbulls in the Paris area.
The reason is not that the dogs are savaging children (though, as in Britain, such incidents are not unknown), but that - according to the police - drug dealers, racist gangs and burglars are increasingly taking pitbulls rather than knives or firearms when they set out for a night's work.
Armed with a dog, it seems, they calculate that they have a weapon of attack and defence, and the police will be reluctant to shoot.
A French dangerous dogs act could be on the statute book soon, though, and woe betide the beast that then goes about his business unmuzzled and with malice aforethought. Even the most sophisticated philosophical arguments about freedom will be insufficient to save him.