Florian Thauvin, a member of the France squad that won the World Cup in 2018, scored one goal and set up another for Odsonne Edouard as Lens found themselves 2-0 ahead late in the first half.

Teenager Djibril Coulibaly pulled one back for Nice with his first senior goal just before the interval and they hit the woodwork twice in the second half.

But Lens made sure of the win through substitute Abdallah Sima, who poked home in the 78th minute to spark joyous celebrations.

The triumph caps a superb campaign for the club from northern France, who finished second in Ligue 1 to a dominant Paris Saint-Germain and qualified for next season's Champions League as a result.

Lens had never previously won the French Cup despite reaching the final three times, most recently in 1998 -- that year they won the league title for the only time in their history.

The vast majority of the near-capacity crowd inside the 80,000-seat Stade de France were supporting Lens, with many disillusioned Nice fans not attending.

Defeat for Nice adds to their misery in a difficult season which is not yet over -- they finished third-bottom in Ligue 1 and must therefore win a two-legged play-off next week against second-tier Saint-Etienne in order to secure their top-flight status.