The 1906 Grand Prix de l'Automobile Club de France, commonly known as the 1906 French Grand Prix, was a motor race held on 26 and 27 June 1906, on closed public roads outside the city of Le Mans. The Grand Prix was organised by the Automobile Club de France (ACF) at the prompting of the French automobile industry as an alternative to the Gordon Bennett races, which limited each competing country's number of entries regardless of the size of its industry. France had the largest automobile industry in Europe at the time, and in an attempt to better reflect this the Grand Prix had no limit to the number of entries by any particular country. The ACF chose a 103.18-kilometre (64.11 mi) circuit, composed primarily of dust roads sealed with tar, which would be lapped six times on both days by each competitor, a combined race distance of 1,238.16 kilometres (769.36 mi). Lasting for more than 12 hours overall, the race was won by Ferenc Szisz driving for the Renault team. FIAT driver Felice Nazzaro finished second, and Albert Clément was third in a Clément-Bayard.
Paul Baras of Brasier set the fastest lap of the race on his first lap. He held on to the lead until the third lap, when Szisz took over first position, defending it to the finish. Hot conditions melted the road tar, which the cars kicked up into the faces of the drivers, blinding them and making the racing treacherous. Punctures were common; tyre manufacturer Michelin introduced a detachable rim with a tyre already affixed, which could be quickly swapped onto a car after a puncture, saving a significant amount of time over manually replacing the tyre. This helped Nazzaro pass Clément on the second day, as the FIAT—unlike the Clément-Bayard—made use of the rims.
Renault's victory contributed to an increase in sales for the French manufacturer in the years following the race. Despite being the second to carry the title, the race has become known as the first Grand Prix. The success of the 1906 French Grand Prix prompted the ACF to run the Grand Prix again the following year, and the German automobile industry to organise the Kaiserpreis, the forerunner to the German Grand Prix, in 1907.
The first French Grand Prix originated from the Gordon Bennett races, established by American millionaire James Gordon Bennett, Jr. in 1900. Intended to encourage automobile industries through sport, by 1903 the Gordon Bennett races had become some of the most prestigious in Europe; their formula of closed-road racing among similar cars replaced the previous model of unregulated vehicles racing between distant towns, over open roads. Entries into the Gordon Bennett races were by country, and the winning country earned the right to organise the next race. Entries were limited to three per country, which meant that although the nascent motor industry in Europe was dominated by French manufacturers, they were denied the opportunity to fully demonstrate their superiority. Instead, the rule put them on a numerical level footing with countries such as Switzerland, with only one manufacturer, and allowed Mercedes, which had factories in Germany and Austria, to field six entries: three from each country. The French governing body, the Automobile Club de France (ACF), held trials between its manufacturers before each race; in 1904 twenty-nine entries competed for the three positions on offer.
When Léon Théry won the 1904 race for the French manufacturer Richard-Brasier, the French automobile industry proposed to the ACF that they modify the format of the 1905 Gordon Bennett race and run it simultaneously with an event which did not limit entries by nation. The ACF accepted the proposal, but decided that instead of removing limits to entries by nation, the limits would remain but would be determined by the size of each country's industry. Under the ACF's proposal, France was allowed fifteen entries, Germany and Britain six, and the remaining countries—Italy, Switzerland, Belgium, Austria and the United States—three cars each.
The French proposal was met with strong opposition from governing bodies representing the other Gordon Bennett nations, and at the instigation of Germany a meeting of the bodies was organised to settle the dispute. Although the delegates rejected the French model for the 1905 race, to avoid deadlock they agreed to use the new system of limits for the 1906 race. But when Théry and Richard-Brasier won again in 1905, and the responsibility for organising the 1906 race fell once more to the ACF, the French ended the Gordon Bennett races and organised their own event as a replacement, the Grand Prix de l'Automobile Club de France.
A combined offer from the city council of Le Mans and local hoteliers to contribute funding to the Grand Prix persuaded the ACF to hold the race on the outskirts of the city, where the Automobile Club de la Sarthe devised a 103.18-kilometre (64.11 mi) circuit. The first and some later layouts had nothing in common with the well known modern track that was first used in 1921.
Running through farmlands and forests, the 1906 track, like most circuits of the time, formed a triangle. It started outside the village of Montfort, and headed south-west towards Le Mans. Competitors then took the Fourche hairpin, which turned sharply left and slowed the cars to around 50 kilometres per hour (31 mph), and then an essentially straight road through Bouloire south-east towards Saint-Calais. The town was bypassed with a temporary wooden plank road, as the track headed north on the next leg of the triangle. Another plank road through a forest to a minor road allowed the track to bypass most of the town of Vibraye, before it again headed north to the outskirts of La Ferté-Bernard. A series of left-hand turns took competitors back south-west towards Montfort on the last leg of the triangle, a straight broken by a more technical winding section, near the town of Connerré. Competitors lapped the circuit twelve times over two days, six times on each day, a total distance of 1,238.16 kilometres (769.36 mi).
To address concerns about previous races, during which spectators crowding too close to the track had been killed or injured by cars, the ACF erected 65 kilometres (40 mi) of palisade fencing around the circuit, concentrated around towns and villages, and at the ends of lanes, footpaths and roads intersecting the track. The planking used to avoid the towns of Saint-Calais and Vibraye was installed as an alternative to the system used in the Gordon Bennett races, where cars passing through towns would slow down to a set speed and were forbidden to overtake. Several footbridges were erected over the track, and a 2,000-seat canopied grandstand was built at the start and finish line at Montfort. This faced the pit lane on the other side of the track, where the teams were based and could work on the cars. A tunnel under the track connected the grandstand and the pit lane. The road surface was little more than compacted dust and sharp stones which could be easily kicked up by the cars, and to limit the resulting problem of impaired visibility and punctures the ACF sealed the entire length of the track with tar. More was added to the bends of the track after cars running on them during practice broke up the surface.
Ten French manufacturers entered cars in the Grand Prix: Clément-Bayard, Hotchkiss, Gobron-Brillié, Darracq, Vulpes, Brasier (the successor to Richard-Brasier), Panhard, Grégoire, Lorraine-Dietrich and Renault. Two teams came from Italy (FIAT and Itala) and one (Mercedes) from Germany. With the exceptions of Gobron-Brillié and Vulpes, which each entered one car, and Grégoire, which entered two cars, each team entered three cars, to make a total field of thirty-four entries. No British or American manufacturers entered the Grand Prix. The British were suspicious that the event was designed as propaganda for the French automobile industry; British magazine The Motor quoted French daily newspaper Le Petit Parisien as evidence of this supposed lack of sportsmanship.