The Siege of Belfort ( 3 November 1870 – 18 February 1871 ) was a 103-day military assault and blockade of the city of Belfort , France by Prussian forces during the Franco-Prussian War .

The Siege of Belfort ( 3 November 1870 – 18 February 1871 ) was a 103-day military assault and blockade of the city of Belfort , France by Prussian forces during the Franco-Prussian War .

Belfort is located in a gap between the mountainous southern Vosges and the Jura Massif , strategically positioned Placing as the gateway between Alsace and central France .

The fall of Strasbourg on 28 September 1870 allowed Preventing_or_letting the German army under August von Werder to move Motion south against Belfort .

Werder 's forces reached Arriving Belfort and invested Besieging the city on 3 November .

General Charles Denis Bourbaki assembled Come_together an army intending to relieve Cause_to_make_progress Belfort .

On 18 February the Belfort garrison marched Self_motion freely out of the city with their weapons and honor .