Automotive History: The Citroën 15-Six – Traction Royalty Genealogy 101

(first posted 10/26/2016, revised in October 2022)     The Citroën 15-Six, colloquially known as the “Quinze” in its native land, was the apex of the automaker’s car range for 18 years, with remarkably few changes. It was the last French-made straight-six and also the first car to feature the famous hydropneumatic suspension. But first, let’s look at Citroën’s context and the Traction Avant range in a bit more depth…

Getting Traction: André Citroën’s Testament Car

1933-34 RWD Citroën “Rosalie” — above: 10 CV (4-cyl.) roadster; below 15 CV (6-cyl.) limousine

The background of the Traction Avant’s birth is one of total chaos. The story begins in early 1933. André Citroën just had the main Javel factory completely re-built, even as car sales plunged due to the Depression. The RWD “Rosalie” range was not selling very well and the creditors were panicking, but Citroën was a betting man. Having just driven the new front-drive Adler Trumpf in Germany, he wagered everything on a completely new car, which was rushed to production in a little over a year.

Flaminio Bertoni (1903-64)


The new car would be a cocktail of the most cutting-edge technology, one-upping the Trumpf and every other car besides: hydraulic brakes, unit body construction, no running boards, torsion bar suspension, brand new OHV engine driving the front wheels, automatic gearbox – all packaged into a beautifully-proportioned, aerodynamic (for 1934) low-slung shape authored by Flaminio Bertoni, who oversaw all Citroën designs between the Rosalie and the Ami 6.

Spring 1934: The little 7, the first Traction Avant to hit the streets.


That was the plan – Citroën’s high-stakes bet. And he almost pulled it off. At the last minute, the troublesome automatic gearbox was nixed and a traditional 3-speed was designed to replace it in three weeks. The Traction quickly entered production, hitting the dealerships in April 1934 and soon evolved into two main ranges – the smaller 7 and the larger 11 – complete with two-door convertible and coupé varieties, as well as LWB limousines.

These early cars had numerous flaws: UV joints would fail, unit bodies were too weak, suspensions too fragile, engine mounts inadequate, etc. Sales quickly nose-dived after the initial summer boom; the many repairs under warranty and constant production changes were further sinking Citroën’s treasury. To top it all, they had stopped producing the Rosalie, thereby leaving those customers who were weary of the new car unable to order anything more traditional.

André Citroën thought he still had an ace up his sleeve: the V8-powered “22”. He ordered the car in pre-production, added it to the brochures and put a few on display at both the Paris and Brussels Auto Shows in October and December 1934. With its 100 hp V8 made from two 11 CV blocks, the 22 was purported to reach speeds of 140 kph (85 mph) “in complete safety”.

The only known photo of the 22 coupé, taken in late 1934 at Citroën’s Champs-Elysées showroom.


A few prototype saloons, and at least one limousine, one roadster and one coupé were photographed in 1934 with their distinctive double bumpers, faired headlights and bespoke grille. They have all since vanished – not a single 22 has been seen in several decades, despite a considerable amount of sleuthing from scores of diligent Tractionnistes in France and abroad.

André Citroën (1878-1935)


On December 21, 1934, the company was officially declared bankrupt. Michelin, Citroën’s tyre supplier and one of their many concerned investors, did a deal with the main creditors, banks Paribas and Lazare, and gained control of the carmaker in January 1935. André Citroën was already very ill by that time; he died of stomach cancer six months later.

UK/Empire markets used different (RAC) tax ratings: the British Fifteen HP was the French 11 CV.

Citroën designed the Traction Avant as three cars. The first was a small body shell for the base 7 range and the performance-oriented 11 Légère. The second was a larger and wider body for the family-minded customer (11 Normale). Though similar-looking, their body panels, width, grilles and roof pressings were all different. Only the front doors were shared across all Traction variants. Both the small and large cars came in saloon and two-door (coupé and roadster) variants. The third member of the species was the six-light Longue body shell, initially used for the 11 and 22 LWB six-seater Limousine and nine-seater Familiale.

Only the 11 was available in all three body variants. Taken from a 1954 brochure.


Early Longues had symmetrical front and rear door openings that looked nice but undermined the body’s structural strength, which always remained inferior to the other two body shells. Not a few LWB Tractions simply broke in half at the B-pillar, even though the Normale‘s rear doors were eventually used to provide a little extra rigidity. Like the aborted 22, the 15-Six would only be available on the Normale and Longue bodies.

11A “Large” roadster — a touch of glamour for the ’34 range…


Turning Lemons Into Lemonade

Soon after Michelin took over, the V8 programme was simply cancelled – it had been launched way before it would be ready for production, yet again. Getting the 22 sorted would have diverted focus from the 4-cyl. cars, which also needed a lot of urgent attention but were showing promise.

Early Michelin-era 4-cyl. saloon (1936): less chrome, single tail light, opening boot, colours besides black still available


Thanks to countless mechanical, structural and production fixes, by late 1936 Citroëns were solid and dependable cars again, but with far better handling and safety than virtually anything on the road. Michelin instilled its penny-pinching conservative values in the Traction, which lost some of its brightwork, made do with only one tail light and fewer paint options. Reintroducing the RWD range (with ‘reversed’ Traction OHV engines) also helped the bottom line.

When the RWD range was pensioned off for good after 1937, the 11 Commerciale utility wagon, based on the Longue, was launched to try to convert French small businesses and rural folk to the wonders of FWD. This version, like all Longues, was dropped from the range during the war, but it famously reappeared with a genuine hatchback rear door for an encore in 1954-57.

A weird one, just for kicks: one of the 550 Citroën 11 BL delivery vans made in Denmark circa 1950.


Now that the Traction had been sorted out, Pierre Boulanger (“Michelin’s man” at the helm of Citroën) could turn his attention to making the front-drive subcompact TPV (Toute Petite Voiture, the 2 CV) and also revisit André Citroën’s original idea: a range-topping luxury model, but not a V8. Something that would work.

Six please, we’re French

The cancellation of the 22 did leave a gap at the top, but the V8 had proven heavy, thirsty and less than brilliant. So a straight-six was programmed instead. Because the last 6-cyl. Citroën, the RWD Rosalie, had been called 15 CV, Citroën decided to keep the numeral, calling the new car 15-Six. However, the car’s fiscal rating was 16 CV, as the Traction’s 6-cyl. was a bit bigger than its ancestor’s unrelated engine.

The new 2.9 litre 6-cyl. was basically the 11’s 4-cyl. with a two extra cylinders. This called for a noticeably longer nose than the 11, though tooling costs were kept under control by using the 11’s front wings and headlights. The 15-Six was a heavier car, with velours seats and a bit more chrome. It could reach over 80mph, though at those speeds, it would gobble about 20 litres of petrol every 100km (12 mpg).

The first batch of cars, all black saloons, were sold to selected clients and field-tested by Citroën or Michelin executives in May-June 1938. The 15-Six was officially launched in October 1938, at what turned out to be the last Paris Auto Show before the war, but only as a saloon; the Limousine and Familiale versions (below) were introduced in March 1939.

Tractions from this era used these attractive Michelin Pilote wheels. The Six’s Pilotes were cream-coloured (the 11 Normale / Longue had red ones and the 7 / 11 Légère’s were bright yellow). The 15-Six’s grille was then painted black and its headlights were fully chromed. Also, the 15-Six sported louvres on its hood from the start – this was only adopted by the 11 in 1946.

Had the 1939 Paris Auto Show taken place, Citroën would have probably introduced the 15-Six roadster. As such, only about three were made in late 1939 and perhaps a couple more in 1946-47. Several replicas have been made subsequently, as well as a few coachbuilt specials, but the one pictured above, the 1939 “Madame Michelin” car, is the only one with a fully traceable history, so it could be the only genuine 15-Six roadster in existence.

First advert for the 6-cyl. range, mid-1938


The Queen Of The Road’s Loyal Opposition

The 15-Six was born at a time when there was a glut of big French cars. I realize this sounds strange, but the ‘30s really was another world. To better understand the Citroën 15-Six’s appeal, let’s see how it compared to domestic cars with similar displacement and status.

Inside the 15-Six – spacious, if not exactly luxurious. Source:

Leaving out super-expensive blue-bloods like Bugatti or Voisin, as well as those that were below 12 CV (Berliet, Rosengart, Simca, etc.), a whopping 17 competitors remain in the 15-Six’s segment. Here they are, sorted in ascending order according to their 1939 list price.

The Citroën’s most dangerous fish in this crowded pond were the Matford V8s and the Renaults: modern-looking, well-appointed and well-built vehicles. But in terms of handling, technological advancement, safety, interior space, speed and value for money, the Citroën was way ahead. Most other marques could best the Citroën in terms of finish or luxury and could be more comfortable, but on the road, the cheaper and roomier 15-Six would always be the car in front. Of all the competitors, only Panhard also used an all-steel unit body construction – Licorne sort of did too, employing a Citroën body shell with a modified floor to mate it with their RWD chassis. Hydraulic brakes remained a minority, whereas independent front suspension was becoming the norm. The only aspect that really let the 15-Six down was its lack of a fourth speed; the popular Cotal electromagnetic gearbox could not be adapted for use on the Citroën.

The “Big Six” barely made it to the British market as a 1940 model


Alas, the new  luxury Traction’s career barely got started that it was overtaken by events: car production in most European countries was drastically cut down by 1940 for obvious reasons. A handful of the Sixes were still being made when Germany invaded France, but from 1941, the 15-Six went on a five-year hiatus. Several privately-owned cars were commandeered by the Germans, a few making it all the way to the Eastern Front.

Post-war Success

In 1946, the 15-Six went back into production, with 203 units made that year. The car was already eight years old, but its moment had finally come.

1947 Citroën 15-Six “G” with a lefty engine; note the new wheels and painted headlamps


The first major modification to the 15-Six took place for MY 1948. The engine up to that point had been “turning left” (anti-clockwise), the opposite of the 4-cyl. Tractions. No one seems to know for sure why the 6-cyl. was designed this way initially. The engine’s rotation was switched to clockwise, necessitated by a new strengthened gearbox. This in turn led to a new grille: the starting handle’s shaft had moved up, the old hole was hidden by a pair of chrome wings. The engine also received a revised head and several smaller modifications – the power output of 77 hp @ 3800 rpm remained the same, though the compression ratio went down slightly, presumably to better cope with the lower quality of post-war gasoline. The first-generation (1938-47) cars retroactively became the 15-Six “G” for “Gauche” (left); the new 15-Six was nicknamed the 15-Six “D” for “Droite” (right).

Peril with a V8…


Competition had thinned out by now: Renault and Panhard switched to small cars; many others had pulled out of car-making or were moribund (Chenard-Walcker, Unic, Licorne, etc.) or aimed further upmarket (Talbot-Lago, Delahaye) to the Bugatti level. Only Ford, Salmson and Hotchkiss were still directly competing with the 15-Six. The new Ford Vedette became the big Citroën’s main rival from 1948: it had a V8, it was comfortable, it had a real boot, it was more modern-looking and glitzier, and it was priced right. But the Vedette was slower, heavier, clumsier and thirstier that the 15-Six, and not as well built.

The 15-Six gradually put on more chrome with bigger hubcaps in 1950 and stouter straight bumpers in 1951.

The most substantial facelift came in late 1952: 18 years into its production run, the entire Traction Avant range was given a bigger boot, new interiors, front and rear turn signals, cowl-mounted windshield wipers and other small changes.

In 1954, the LWB models, which had been mothballed since the war, returned to the 11 and 15-Six ranges. Also, Tractions could now be ordered in blue or gray, though most still came out black.

In April 1954, the upcoming DS’s famous hydro-pneumatic suspension was debuted on the 15-Six’s egregiously rigid rear axle, becoming the “15-Six H”, though the normally-sprung 15-Six remained available through 1955.

Inside, the 15 H was less gloomy, though still very basic. Photo: Ph. Losson

Typical of late Traction dashes, the 15 H was less gloomy, though still rather basic. Source: Ph. Losson


The 15 H had the same engine but with a higher compression ratio, making it slightly more powerful (80hp @ 4000 rpm) and a bit quicker than the previous Six. To try and match the softer rear suspension, the 15 H had much longer torsion bars at the front, which stuck out on either side of the bottom of the grille.

15 H, rear view: newly added right-hand tail light has pushed the “15 6-cyl” badge to the trunk lid


This final iteration of the 15-Six was really a test-bed for the innovative suspension, though it did provide the fortunate few who could afford one, as well as a chauffeur, a level of comfort hitherto unknown in the back of a Traction. Production of all Citroën sixes stopped in 1956, as DS production ramped up.

From pre-war to space age in two letters: DS


The Traction Avant In Numbers

Just over 50,000 Citroën 15-Six G, D and H were made from 1938 to 1956, out of a total production of 759.111 Traction Avants (1934-1957). These may seem like paltry numbers by today’s standards, but in fact the 15-Six sold in much larger quantities than all its competitors (except Ford) and effectively captured the market for executive cars in France after the war.

Production was still ramping up when the war came; less than 2500 cars had been sold by 1940. The 15-Six’s top-selling year was 1951 with 11,752 units sold, similar to the one above. The only year it cracked the five-digit mark was twelve years after its debut, and five years before retirement. Some cars sure take their time to peak. As the very final innovation of the breed, the 15 H is usually considered to be a distinct model, though part of the 15-Six family. A little over 3000 were made in two years.


Six Specials And Foreign-Built Saloons

Coty’s personal 15 H limo, specially-made by Citroën in late 1956 – perhaps the very last 15-Six built.

Coty’s personal 15 H limo, specially-made by Citroën in late 1956 – perhaps the very last 15-Six built.


In 1955, French president René Coty, an older man with health problems, was recommended Citroën’s hydro-pneumatic suspension by his physician. He personally ordered a 15 H limousine (one of only two ever made, as the 15 H was only produced as a saloon), soon after having two new official state cars built on a stretched Citroën 15 H platform to replace both his predecessor’s Talbot-Lago convertible and Marshal Pétain’s 1942 Renault Suprastella town car.

The first 15 H-based state car was a limousine designed by Philippe Charbonneaux and bodied by Franay in 1955 – the coachbuilder’s final piece before closing shop.

De Gaulle likely approved his predecessor’s choice in cars: his personal car was also a 15 H


The second presidential 15 H, a four-door convertible parade car, was made by Henri Chapron in 1956. Its peculiar beltline dip was designed by Carlo Delaisse so that the VIP likely sitting there might be better seen by the happy taxpayer in the street. These were in service until about 1974, when these and several other state cars were (bizarrely) donated by president Pompidou to one of his doctors. By all accounts, these cars’ longer and substantially heavier ash-framed bodies were very tough on the 80hp engine, so these were not usually driven on the open road, unlike the Citroën SM phaetons that replaced them.

1953 Citroën 15-Six coupé by Beutler


Other interesting designs include the Swiss coachbuilt cars. The Traction was quite a hit outside France. Countries without large national automakers to turn to such as Austria, Scandinavia, Spain, Portugal, Benelux or Turkey were keen importers, as were the Swiss.

1952 15-Six cabriolet by Langenthal, boldly integrating the headlamps into the fenders…

I caught the same car six decades later. Langenthal made 40-odd 11-based convertibles, but only two 15-Six.


Switzerland also had several world-class master coachbuilders, such as Worblaufen, Beutler, Graber and many others. The great contribution of these coachbuilders was to provide a trickle of genuine two-door Tractions, which the Citroën factory was no longer making after the war.

Above: Figoni & Falaschi’s mercifully unique 1952 15-Six “Le Squale” coupé; below: ’48 Antem limo

By contrast, French carrossiers we not as inspired as their Swiss colleagues by the 15-Six (or by Citroëns in general in those days). The limousine above, an instersting illustration of the challenges many coachbuilders were facing with the spread of unit bodies. It’s clearly a pre-war LWB 15-Six body shell with heavily customized wings, a bigger trunk and a remodeled front end. The result is not exactly an improvement on the original.

One singular innovation was Georges Regembeau’s handful of genuinely fast Sixes, made in the mid-’50s. The only visible differences were the wire wheels, fatter tyres and a touch of extra brightwork. The engine was reassembled and finely tuned, given a supercharger and fuel injection, as well as a six-speed box and special brakes. Power jumped to 195 hp and one was clocked on the Montlhéry racetrack at 210 kph (130 mph).

A few dozens of cars were transformed by specialists to have a canvas roof – the découvrable”, a fad that hit its peak in the ‘50s. This 15-Six has an AEAT roof, as well as an aftermarket Grégoire suspension, designed by engineer Jean-Albert Grégoire, a FWD pioneer in his own right. These Grégoire all-alloy IRS set-ups were a welcomed improvement over the Traction’s notoriously stiff ride.

The Traction Avant was sold in many countries, but it was only made in three. Citroën had an assembly plant in Forest, Belgium, which assembled CKD cars from 1926 to 1980. Belgian-built Tractions, like the 15-Six above photographed at the 1951 Brussels Motor Show, had locally-sourced wheels, grilles, semaphores and other small details, and were available in colours other than black.

Mid-‘50s UK-made Six still has B-pillar semaphores and tiny sidelights instead of turn signals on front wings


Tractions coming from the Citroën factory in Slough, Buckinghamshire, were also available in several hues. The cars also had very nice leather interiors. Many British-sourced components were used, including Smiths instruments for the lovely wood-clad dash, and oversized headlamps and electrics courtesy of Lucas “Prince of Darkness,” Ltd.

Older car (1950) with characteristic gentleman’s club atmosphere


A good condition 15-Six can fetch €40,000-50,000. That’s ‘60s Cadillac money for the best ‘50s car the ‘30s ever gave us. It’s a bargain, it’s a steal. Speaking of which, this was probably the most successful getaway car of the ’40s and ‘50s. So successful that even the French police had to buy a few to keep up with the people they were trying to catch.

Due to the car’s long production run and multiple variants, there are two broad camps among Traction Avant connoisseurs: those who want the extra oomph and prestige of the Six, and those who prefer the lighter 4-cyl. cars. And it’s true that the latter are pretty irresistible, especially in pre-war roadster form.


So that was the story of the Citroën Traction Avant in general and the 15-Six in particular. It was beloved by everyone from bank CEOs to bank robbers. It was also the last French straight six ever made. They called it “la reine de la route” (Queen of the road), but human French royals were nowhere near as successful as this mechanical one.


Related CCs:

Curbside Classic: Citroen 11CV – A Traction Avant Sends Its Greetings From Switzerland, by Paul Niedermeyer

History Outake: Avant-Garde Traction Avant 22 CV, by Robert Kim

Classique de Traffic Parisienne: Citroen Traction Avant, by Jim Klein

Curbside Classic: Citroen Traction Avant en Indochine, by Robert Kim

Curbside Classic: 1950 Citroën 15-Six – Double Oxymoron (Austere Luxury, Old-fashioned Avant-garde), by Tatra87