Stabbing yourself with the oyster-knife ranks pretty high on the list of French gastronomic risks - not far behind bruising your eye (or worse) with a wayward champagne cork. Which is why, last autumn, a Breton by the name of Yves Renaut might have thought his fortune assured.
He had invented and patented a better oyster-opener, and expected to see it in production just in time for France's peak oyster-eating season of Christmas and New Year. Alas, it was not to be.
Instead, the invention became the subject of litigation between the North Breton oyster-cultivators, to whom he had sold a licence to exploit the patent, and a recently constituted company inexplicably named Fizz, to which the oyster-growers had subcontracted development of the opener.
The genius of the invention was that it enabled the oyster to be opened easily without any special implement - indeed, without any implement at all. A thin wire was implanted in the oyster during cultivation, with one end protruding; when the oysters were brought to table, the wire would function like a cross between a tin-opener and a zip-fastener.
The busy host or hungry guest would simply draw it between the two halves of the shell: a twist of the lemon, and the oyster was ready. No scarred hands, no stabbed neighbours.
Whatever the benefits, though, the oyster wire immediately became a subject of controversy, and not just among the professional oyster-openers whose livelihood seemed threatened. The main question, inevitably, was the gastronomic one: didn't the wire impair the size or taste of the oyster?
Mr Renaut insisted that tests had shown wired oysters to be just as plump and tasty as unwired oysters, but the wire had to be of a special sort and it had to be implanted in particular conditions. Moreover the wires had to be inserted by hand, and one person could manage a maximum of 150 an hour. The prospect of unemployment for the professional oyster-openers receded, as did the likelihood of wired oysters for Christmas.
The North Breton oystermen meanwhile had encountered further difficulties. In their tests, an unacceptable proportion of the wired oysters died. Production was further delayed.
Fizz, for its part, had sold distribution rights to a leading French supermarket chain and complained that development was too slow. The North Breton oystermen objected that they had bought the right to market as well as develop the wire and went to court. The judge at Morlaix in Brittany has just found in their favour. Rights to the oyster wire lie with the cultivators, and the French are unlikely to be unzipping their oysters much before next Christmas, if then.
One invention that has gone entirely as planned is the do-it-yourself breathalyser. Last summer, even as the French government was putting the finishing touches to new drink-drive restrictions - snappy slogan: "After more than two glasses, it all goes much faster" - the marketing men were perfecting their response.
This was a disposable breathalyser, mass-produced and sold over the counter for 10 francs (about pounds 1.30) in supermarkets, service stations, restaurants and bars - the very places where people might want to know whether it was safe for them to drive.
I can imagine the frown on the face of the British policeman already. "The do-it-yourself breathalyser won't be reliable, it will give drivers a false sense of security. If you think you need to take the test, you clearly should not even be thinking of driving . . . it will encourage drivers to argue, to contest the charge . . ."
Here, they take a different view. The authorities think the do-it-yourself test could encourage a sense of responsibility, while drivers want to know the odds - not to contest the validity of the police test, just to calculate their chances.
The availability of the test may or may not cut drink driving and the related accidents - alcohol is said to be a factor in one in three accidents in France - but it probably won't increase it. On the other hand, it will not decrease the incidence of champagne cork injuries. French inventors: there lies your next challenge.