Paris -- Soon after the turn of the 20th century, Marcel Leyat, like many mechanically inclined young men, decided to build a motorcar.
What emerged from Leyat's Paris workshop in 1913 was a car like none before or since. The Hélica dispensed with bourgeois features like a chassis, a transmission and front-wheel steering. Up front, Leyat mounted a huge propeller, and the driver and passenger sat fore and aft in a canvas-covered cockpit. A chain connected to a steering wheel turned the rear wheels.
He sold two dozen.
"Levat was an aviator," Claude Guenifféy, an expert on the Hélica, said Wednesday at the Levat display at Retromobile, the vast classic car exhibition here. "So when he decided to build a car he built one like a plane without wings."
But while the Hélica appears to have descended to Earth from another planet, it slots neatly into the French carmaking tradition of, well, ignoring tradition pretty much altogether.
The full flowering of French ingenuity is on display at Retromobile, now in its 38th year at the Paris Expo center in the south of the city. Over five days, an expected 75,000 visitors will take in displays of hundreds of landmark vehicles from Les Grands Trois -- Renault, Citroën and Peugeot -- and giants of the golden age of motoring like Bugatti, Talbot-Lago and Delahaye. Vendors in the cavernous hall offer vintage Art Deco racing posters, orphaned Lalique hood ornaments and refurbished steering wheels.
Mr. Guenifféy is one of the few people who can answer this burning question about the Hélica, of which only two survive: How does it handle?
"It's like driving a big ventilator," he said, laughing. "It makes a lot of noise. It's very strange and scary."
Well, it isn't all that bad, said Jeff Lane of the Lane Motor Museum in Nashville, who built a replica Hélica using plans that Mr. Guenifféy discovered in a vineyard building in 2004. Because the Hélica is essentially powered by a stiff breeze, it takes a couple of minutes to reach 30 m.p.h.
In sharp contrast to Leyat's spindly machine, my eye was drawn to a cascading 1937 Delahaye in two-tone sky blue and cream, the automotive equivalent of a perfectly coifed Afghan hound. I struck up a conversation with a polished older gentleman in double-breasted coat and pocket square, who told me that the coachwork was actually a re-creation of a Figoni et Falaschi design that was fabricated by Auto Classique Touraine.
He opened the door of a 1937 Bugatti 57 Atalante and pointed to the tobacco-colored leather interior in the sleek coupe. "Hermès," he said. "Alligator."
"Patrick," he said, introducing himself. "Patrick Delage." Could it be? Mais oui! Indeed he said he was the great-grandson of Louis Delage, the creator of the legendary Delage, a luxury rival to the more sporting Bugattis that was later acquired by Delahaye.
But life isn't all chocolate and Champagne. The French have created legendary quotidian cars, too, infusing econoboxes with a little joie de vivre. While there are just a handful of space-oddity Citroën 2CVs still doddering around Paris, swarms of smooth-riding Renault 5s (known in America as Le Car) and Peugeot 205s still zip along the country's village lanes and cobblestone streets.
Last year, the Renault 5 had its day at Retromobile, 2012 being its 40th anniversary, so this year it was the 205's turn, the banty Peugeot celebrating 30 years.
"I call it a 'no filter' car, with direct feeling controls," said François-Xavier Basse, the editor of Youngtimers magazine, which is devoted to the cars of 1970-90.
Like millions of French youth, his first car was a 205. "Even today, it's very modern," he said. "It was the first exciting car from Peugeot in the period," replacing the stodgy 104. The 205, designed in 1983, competed with the Renault 5.
Peugeot nailed it: The company sold 5.3 million 205s over 15 years, including the pocket-rocket 205 GTI and a ferocious turbocharged rear-engine version that won the fabled Group B rally championship in 1985. Appropriately, for a car that can be had now for about $1,300, one of the base-model 205s on display had a quarter-size rust hole near the rear window.
The various strands of French design came together in the Citroën DS, introduced in 1955 at the Paris Salon de l'Auto, causing such a sensation that 80,000 people immediately slapped down their hard-earned francs as a deposit.
A grinning shark's mug capped a cigar-shaped torso that tapered toward the rear. A complex hydraulic system controlled a self-leveling suspension, power disc brakes, a semiautomatic gearbox and power steering. In later models, the front headlights pivoted with the steering, which was controlled by a wheel with a single spoke. Because, hey, who needs two?
And even better for style-conscious Parisiens, the DS came in a rainbow of pastel shades.
"The DS means revolution," said François Melcion, the director of Retromobile. "And the French, we like revolution.''
The heart of the DS line was always the four-door sedan, but the main display at Retromobile -- the private collection of the Swiss dealer Lukas Huni, and meant to mimic the 1955 debut -- also includes the hangarlike Safari wagon and a few of the coachbuilder Henri Chapron's slender cabriolets, which can fetch six-figure prices at auction.
Though parts of Retromobile seemed a sea of French racing blue, foreign marques made a strong showing. Mercedes brought one of its record-setting 1909 Blitzen-Benz streamliners, powered by a 21.5-liter engine.
And should the typical high-end auction fare prove too tame -- the star of the Artcurial catalog at Retromobile is a 1936 Talbot-Lago T150C that soldiered on to race at Le Mans four times until 1949, and carried a presale estimate of $1.6 million to $2.2 million -- a Dassault Mirage V attack jet was to be auctioned on Friday. But unlike the daredevil drivers of Marcel Leyat's propeller cars, any buyer of the Mirage who hopes to take it to the air would certainly need a pilot's license, if not actual combat experience.
This article originally appeared in The New York Times.