In the Franco-Prussian War, many citizens of Bethoncourt fled from the Prussians across the border to Switzerland, where many had relatives in the Swiss Jura region.

In the early twentieth century, Bethoncourt grew from a small town into a thriving city of nearly 11,000 inhabitants.

Bethoncourt possessed rich iron mines that provided ore for all the foundries in the region in such towns as Chagey and Audincourt.

The ore was brought to a washing station (still extant), a sort of lock on the Lizaine between Bethoncourt and Bussurel.

However, the entire Jura watchmaking industry was hit hard by the importation of cheap factory-made American watches, which were of equal or higher quality.