Franco-Prussian War (1870-1871): Fall of the Second Empire

The Franco-Prussian War, also called the Franco-German War, was fought from July 1870 to May 1871 between France and a coalition of German states led by Prussia. In a few weeks German armies destroyed or trapped the main French field forces, captured Emperor Napoleon III at Sedan and besieged Paris. The war ended the French Second Empire, created the German Empire and left a legacy of bitterness over Alsace-Lorraine that shaped European politics until 1914.

Background: a contest for leadership in Europe

After Prussia’s victory over Austria at the Battle of Königgrätz in 1866, Bismarck united the states north of the River Main in the North German Confederation. The southern states of Bavaria, Württemberg, Baden and Hesse-Darmstadt remained outside it, though bound to Prussia by secret military alliances.

In France, Napoleon III had hoped to gain territorial compensation for his neutrality in 1866, perhaps in the Rhineland, Belgium or Luxembourg. His attempts failed, and French public opinion felt humiliated by Prussia’s rise. “Revenge for Sadowa” became a popular slogan. The Second Empire was also under domestic pressure and had only recently turned into a more liberal, parliamentary regime.

Bismarck believed that a war with France, presented as French aggression, would rally the southern German states to Prussia and complete German unification. Historians still debate how far he planned the war in advance, but he certainly exploited the crisis of 1870 skilfully.

The Hohenzollern candidacy and the Ems Dispatch

In 1868 a revolution in Spain deposed Queen Isabella II, and the Spanish government looked for a new king. In 1870, with Bismarck’s encouragement, it offered the throne to Prince Leopold of Hohenzollern-Sigmaringen, a relative of the Prussian king. France saw this as encirclement by the Hohenzollerns and protested strongly.

Leopold’s candidacy was withdrawn on 12 July 1870. The French government, however, sent its ambassador, Vincent Benedetti, to meet King Wilhelm I at the spa town of Bad Ems on 13 July and demand a guarantee that the candidacy would never be renewed. The king politely refused and declined a further meeting.

Wilhelm sent Bismarck a telegram reporting the conversation. Bismarck shortened it for publication so that it seemed the king had snubbed the ambassador and the ambassador had insulted the king. The edited Ems Dispatch was released to the press on the evening of 13 July. It caused outrage in Paris, and on 19 July 1870 France declared war on Prussia. As Bismarck had hoped, the southern German states joined Prussia at once.

Bismarck later boasted in his memoirs that he had edited the telegram to provoke France, and this account long shaped popular memory. Historians accept that the edit was deliberately provocative, but they also stress that the French government and press were eager for a confrontation and that Napoleon III’s ministers chose war with little hesitation.

The German invasion

Under the direction of Helmuth von Moltke, the German armies mobilised quickly by rail and concentrated near the frontier in three armies. France had a fine infantry rifle, the Chassepot, which outranged the Prussian needle gun, and an early machine gun, the mitrailleuse. But French mobilisation was confused, reserves were slow to arrive and the Germans soon had a large numerical advantage. German steel breech-loading artillery made by Krupp proved decisive in battle after battle.

After a minor French move on Saarbrücken on 2 August, German forces invaded Alsace and Lorraine. They won at Wissembourg on 4 August and at Wörth (Froeschwiller) and Spicheren on 6 August. Marshal Patrice de MacMahon’s army retreated from Alsace, while Marshal François-Achille Bazaine’s Army of the Rhine fell back towards the fortress of Metz.

Two of the bloodiest battles of the war followed: Mars-la-Tour on 16 August and Gravelotte–St Privat on 18 August. Casualties on both sides were very heavy, but the result was that Bazaine’s army of roughly 180,000 men was shut inside Metz.

Sedan and the fall of the Empire

MacMahon formed a new army at Châlons and, accompanied by Napoleon III, marched north-east to try to relieve Metz. German armies under the Crown Prince of Prussia and the Crown Prince of Saxony caught it at Sedan near the Belgian border. On 1 September 1870 the French were encircled and shelled from the surrounding heights. The next day Napoleon III surrendered with about 100,000 men, as told in our article on the Battle of Sedan.

When the news reached Paris, crowds invaded the legislature, and on 4 September 1870 republican deputies, including Léon Gambetta and Jules Favre, proclaimed the Third Republic at the Hôtel de Ville. A Government of National Defence under General Louis-Jules Trochu decided to continue the war.

The war of the Republic

German armies reached Paris and completed its encirclement on 19 September. The Siege of Paris lasted more than four months. Gambetta escaped from the city by balloon on 7 October and organised new armies in the provinces from Tours.

These improvised forces fought with courage but limited training. The Army of the Loire won a victory at Coulmiers on 9 November and briefly retook Orléans, but was defeated in December. Other French armies fought in the north and east. Irregular fighters known as francs-tireurs harassed German supply lines, provoking harsh reprisals against villages.

The worst blow came on 27 October, when Bazaine surrendered Metz with some 140,000–180,000 men, depending on how the sick and wounded are counted, freeing German troops to fight on the Loire. Strasbourg had already surrendered on 28 September after a heavy bombardment. In January 1871 General Charles Bourbaki’s Army of the East was driven against the Swiss border, and some 87,000 men crossed into Switzerland to be interned in early February.

Armistice and peace

On 18 January 1871, while Paris was still under siege and bombardment, Wilhelm I was proclaimed German Emperor in the Hall of Mirrors at Versailles. Ten days later, on 28 January, starving Paris accepted an armistice.

A newly elected National Assembly met at Bordeaux and chose Adolphe Thiers as head of the executive. Preliminary peace terms were signed at Versailles on 26 February, and the final Treaty of Frankfurt was signed on 10 May 1871. France ceded Alsace, except Belfort, and the north-eastern part of Lorraine including Metz. It agreed to pay an indemnity of 5 billion francs, with German troops occupying parts of France until it was paid. France paid ahead of schedule, and the last occupying troops left in September 1873.

In Paris, anger at the defeat and at the conservative Assembly helped spark the revolutionary Paris Commune in March 1871, which French government troops crushed in May.

Key people

• Otto von Bismarck: Prussian minister-president and federal chancellor who used the war to unify Germany.
• Helmuth von Moltke: Prussian chief of staff, the architect of the German campaign.
• Napoleon III: Emperor of the French, captured at Sedan and deposed.
• Léon Gambetta: republican leader who organised national resistance after Sedan.
• Wilhelm I: King of Prussia, proclaimed German Emperor in January 1871.

By the numbers

Casualty figures vary between sources; these are commonly cited estimates.

Consequences and legacy

The war transformed Europe. Germany, now united under Prussian leadership, became the strongest power on the continent. France lost territory, population and prestige, but the Third Republic, born in defeat, survived to become the longest-lasting French regime since 1789.

The annexation of Alsace-Lorraine, made largely for military reasons and against the wishes of most of its inhabitants, poisoned Franco-German relations. The statue representing Strasbourg on the Place de la Concorde in Paris was draped in black for decades. The idea of revanche, recovering the lost provinces, remained a powerful force until France regained them after the First World War.

The war also had a heavy human cost beyond the battlefield. Hundreds of thousands of French prisoners were held in camps in Germany through the winter of 1870–1871, and a smallpox epidemic spread among soldiers and civilians in both countries. Villages in the war zone were requisitioned, burned in reprisals or shelled, and refugees fled from Alsace and Lorraine both during the war and after the annexation, when residents were given the option of keeping French nationality by moving to France.

Militarily, the war confirmed the importance of railways, general staffs and rapid mobilisation. Every major European army studied the Prussian model, and plans for mass conscript armies moved by rail shaped the opening of the First World War in 1914. The humiliation of 1871 was symbolically reversed when the Treaty of Versailles was signed in the same Hall of Mirrors in June 1919.

Timeline

• 1870, 13 July: The Ems Dispatch is published.
• 1870, 19 July: France declares war on Prussia.
• 1870, 6 August: German victories at Wörth and Spicheren.
• 1870, 18 August: Battle of Gravelotte–St Privat.
• 1870, 2 September: Napoleon III surrenders at Sedan.
• 1870, 4 September: The Third Republic is proclaimed in Paris.
• 1870, 19 September: The siege of Paris begins.
• 1870, 27 October: Bazaine surrenders Metz.
• 1871, 18 January: The German Empire is proclaimed at Versailles.
• 1871, 10 May: Treaty of Frankfurt ends the war.

Why it matters

The Franco-Prussian War created modern Germany, brought down France’s last monarchy and set the stage for the rivalry between the two countries that led to two world wars. Its battles also marked the arrival of industrial, rail-borne warfare in Western Europe.