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Siege of Paris, 1870-1871: four months behind the walls

Franco-Prussian War · 19 September 1870 to 28 January 1871 · France vs the German states · ~5 min read · Updated October 2026

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Allegorical painting: a woman in a lion skin, standing for Paris, holds a French tricolor above a field of dead and wounded soldiers, gunners work a cannon behind her, and a dark spectre with an eagle hovers in the smoky sky.

Ernest Meissonier, Le Siège de Paris (1870-1884), Musée d'Orsay, Paris, via Wikimedia Commons, public domain.

At a glance

France (Government of National Defense)General Louis Jules Trochu; General Auguste Ducrot; General Joseph Vinoy; Léon Gambetta
vs
Prussia and the German statesKing William I; General Helmuth von Moltke; Otto von Bismarck; Crown Prince Frederick William
Date
19 September 1870 to 28 January 1871 (encirclement completed 17 to 19 September)
Location
Paris, France
War
Franco-Prussian War
Outcome
Paris capitulates on 28 January 1871; armistice and the end of the war
Balloons
First balloon out of Paris, the Neptune, on 24 September; 2.5 to 3 million letters carried by balloon during the siege (French armed forces research institute IRSEM)
Consequence
Germany annexes Alsace and northern Lorraine; the Paris Commune follows in the spring
Quick answer

What happened in the Siege of Paris?

After the French army and Napoleon III surrendered at Sedan on 1 September 1870, Paris proclaimed a republic and refused Prussia's peace terms. German armies closed a ring around the capital on 17 to 19 September and laid siege to it for more than four months. The only link with the rest of France was by balloon; Léon Gambetta flew out on 7 October to raise new armies, but every attempt to break the siege failed. Starving and under bombardment, Paris capitulated on 28 January 1871.1

On 1 September 1870 the army of the Emperor Napoleon III, and Napoleon himself, surrendered to the Germans at Sedan. It seemed the war was over. But on 4 September, in reaction to the news, a swift and bloodless uprising in Paris overthrew the empire and proclaimed, for the third time, a French republic.2

The new Government of National Defense was makeshift. General Louis Jules Trochu, named military governor of Paris on 17 August, became its president; Jules Favre took foreign affairs; the radical firebrand Léon Gambetta became minister of war and the interior; and the old statesman Adolphe Thiers set out to plead France's case abroad. Bismarck's terms were the cession of all of Alsace and of northern Lorraine with Metz. Favre rejected them indignantly.3

The ring closes

Helmuth von Moltke, the Prussian chief of staff, had already sent the German armies westward to surround the capital. On 17 and 18 September German troops took up their positions around Paris, the Crown Prince's army swung south and west to complete the ring, and King William I set up his headquarters at Versailles. Accounts differ by a day or two: the French military research institute IRSEM dates the encirclement by the Prussian uhlans to 18 September, while the EBSCO account says the siege officially began on the 20th, after the last negotiations collapsed.4

Inside the walls Trochu's conduct of the defense remains controversial. He kept almost purely to the defensive, and to some he seemed to have given up hope of victory and to be playing for time; others believed he was bound by honor to resist as long as he could. His second in command, General Auguste Ducrot, argued constantly for attacks on the German lines.5

Letters by balloon

With every other link to the outside cut, Paris turned to the air. On 19 September Gambetta ordered three balloons to be built, and the first, the Neptune, rose on 24 September with 125 kilograms of official dispatches, newspapers and letters. Seamstresses, 120 of them, worked without rest at the Gare de l'Est sewing balloons 16 meters across, which were filled with the city's gas. By IRSEM's count 2.5 to 3 million letters left Paris this way during the siege, some of them meeting a tragic fate.6

On 7 October, at 10:30 in the morning, Gambetta himself climbed into the balloon Armand-Barbès, accompanied by a second balloon, the George Sand. The flight was dramatic. Drifting over the German lines near Épinay, Chantilly and Creil, the balloon came under rifle fire; the crew threw out ballast to climb, and the rain pushed them off course. After five hours in the air the Armand-Barbès came down at 3:40 in the afternoon in the top of an oak in the woods of Favières, in the Oise. French peasants helped the three passengers, who reached Tours, where the government's delegation sat, two and a half days later.7

The sorties fail

In the provinces Gambetta raised new armies, and one of them won a victory at Coulmiers on 9 November. Inside Paris a great sortie was planned to meet it. It went wrong from the start: Trochu and Gambetta were only vaguely aware of each other's movements, the Crown Prince saw the attack coming, and flooding on the Marne delayed it by a crucial day. On 29 November Ducrot's sortie won some early ground but failed by nightfall against an entrenched enemy, while Gambetta's army was halted and thrown back beyond Orléans. It was the last serious attempt to lift the siege.8 › Battle of Coulmiers, 1870

Hunger and the guns

Shortages became acute. Nearly all the animals of the zoo were eaten, and meat from dogs, horses, cats and even rats was sold in the butcher shops. Deaths from hunger, disease and cold rose sharply as winter came, especially among children. By January the privations of the Parisians were winning them sympathy abroad. To break the city's resistance before any foreign intervention, the Germans began a massive bombardment that was condemned internationally but had the desired effect.9

On 22 January Trochu was replaced by General Joseph Vinoy, and negotiations between Favre and Bismarck led to the capitulation of the city on 28 January 1871. IRSEM notes that despite Gambetta's efforts, the run of defeats forced France to sign an armistice early in that year.10

What the siege left behind

The war cost France Alsace and northern Lorraine, and William I had already been proclaimed emperor of a united Germany. The humiliation of the siege fed the anger that exploded in the Paris Commune that spring, and the memory of the shelling of the city added to the politics of revenge that helped lead to the First World War. Yet the long defense also redeemed some of the shame of Sedan and helped the young Third Republic survive its early years. The balloon post, for its part, is remembered in France as the beginning of airmail.11

Notes

A number in the text points to a note; each note names the works that paragraph draws on, listed in full under Sources.

  1. EBSCO Research Starters, “Prussian Army Besieges Paris”; Capt. Aurélien Poilbout and Sgt. Fanny Boyer, “Le 7 octobre 1870, Gambetta échappe au siège de Paris à bord du ballon Armand-Barbès”. ↩
  2. EBSCO Research Starters, “Prussian Army Besieges Paris”. ↩
  3. EBSCO Research Starters, “Prussian Army Besieges Paris”. ↩
  4. EBSCO Research Starters, “Prussian Army Besieges Paris”; Capt. Aurélien Poilbout and Sgt. Fanny Boyer, “Le 7 octobre 1870, Gambetta échappe au siège de Paris à bord du ballon Armand-Barbès”. ↩
  5. EBSCO Research Starters, “Prussian Army Besieges Paris”. ↩
  6. Capt. Aurélien Poilbout and Sgt. Fanny Boyer, “Le 7 octobre 1870, Gambetta échappe au siège de Paris à bord du ballon Armand-Barbès”. ↩
  7. Capt. Aurélien Poilbout and Sgt. Fanny Boyer, “Le 7 octobre 1870, Gambetta échappe au siège de Paris à bord du ballon Armand-Barbès”. ↩
  8. EBSCO Research Starters, “Prussian Army Besieges Paris”. ↩
  9. EBSCO Research Starters, “Prussian Army Besieges Paris”. ↩
  10. EBSCO Research Starters, “Prussian Army Besieges Paris”; Capt. Aurélien Poilbout and Sgt. Fanny Boyer, “Le 7 octobre 1870, Gambetta échappe au siège de Paris à bord du ballon Armand-Barbès”. ↩
  11. EBSCO Research Starters, “Prussian Army Besieges Paris”; Capt. Aurélien Poilbout and Sgt. Fanny Boyer, “Le 7 octobre 1870, Gambetta échappe au siège de Paris à bord du ballon Armand-Barbès”. ↩

Sources

Frequently asked questions

When was the Siege of Paris?

From the encirclement of the city on 17 to 19 September 1870 to its capitulation on 28 January 1871, during the Franco-Prussian War.

Why was Paris besieged in 1870?

After Napoleon III surrendered at Sedan, Paris proclaimed a republic and refused Bismarck's terms, the cession of Alsace and part of Lorraine, so the German armies surrounded the capital.

How did Paris communicate during the siege?

By balloon. The first, the Neptune, left on 24 September 1870, and according to IRSEM 2.5 to 3 million letters were carried out by balloon during the siege.

How did Gambetta escape from Paris?

On 7 October 1870 he flew out in the balloon Armand-Barbès, came under German fire, landed in an oak in the Oise after five hours and went on to Tours to organize new armies.

How did the Siege of Paris end?

Hunger, failed sorties and a German bombardment forced the city to capitulate on 28 January 1871, and France signed an armistice.

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