Simmenauer first began karting in 2012 with Italian team Tony Kart. In 2015, he claimed the title in the French Karting Championship.
Toyota Racing Series
In December 2016, it was announced Simmenauer would make his debut in single-seaters in the Toyota Racing Series, replacing reigning champion Lando Norris, following the latter's decision not to defend his title.[2]
Formula Renault 2.0
In January 2017, Simmenauer joined JD Motorsport for the Formula Renault Eurocup.[3] He went on to experience a disappointing campaign, failing to score points in a season he would end 27th in the standings.
Sportscar career
Porsche Cup
Simmenauer switched to sportscar racing in 2018, driving for Lechner Racing in the Porsche Carrera Cup Germany. With a best result of sixth at the Nürburgring the Frenchman ended up 12th in the standings, having missed one of the seven rounds. In the middle of the season, Simmenauer made his debut in the Porsche Supercup, driving in the Silverstone event. The following year, another season of PCCG would be in store for Simmenauer, who would start a further four races in the Supercup. Once again with Lechner Racing, his best individual placing improved to fourth at the Norisring, though a number of retirements dropped him to 15th in the championship.