Indeed, as a result of the Treaty of Frankfurt which ended the 1870 war, France lost Alsace and Lorraine, reducing its borders.

When a defensive reorganization occurred in France in 1874, the commune of Bron was therefore included in the crown of detached forts, to protect the stronghold of Lyon.

But advances in artillery quickly made these forts, and therefore that of Bron, ineffective, inadequate and unable to defend Lyon.

The fort is located at shooting distance by antique cannon from Lyon (i.e. 7 to 8 km), at 212 metres above sea level on a hill at Bron.

The bridge that allows access to the rear entrance of the fort is unique: it retracts sideways, sliding on steel rollers.

Like other forts, military land was bounded by stone posts located around it, their hats on an engraving showing the direction of the next point.

On 23 September 1976 at the Extra-Municipal Planning Commission (CEMU), the COURLY proposed to transform the ditches to public landfill, to abandon the rubble, and to finally abort the project.

[2] The Fort de Bron is managed by an association created March 25, 1982, which organises free tours on the first Sunday of each month.