Flörsch combined her 2020 FIA Formula 3 Championship commitments with a debut in prototype racing, skipping the Spa-Francorchamps Formula 3 Round to enter the Le Castellet 240 with Beitske Visser for Richard Mille Racing Team in the LMP2 class of the 2020 European Le Mans Series instead. The campaign also included entry into the 2020 24 Hours of Le Mans, where she finished in 9th place alongside Visser and Tatiana Calderón.