The Semi-Marathon de Thionville is a road-race event in Thionville, in Moselle, Grand Est, close to the France-Luxembourg-Germany border area often called the pays des trois frontières. The main race covers the standard half-marathon distance of 21.0975 km, and the programme also includes a 10 km race. The half marathon starts in the morning from Boulevard Foch, with a separate handisport start just before the main field and the 10 km following later. Both races carry regional labels and can qualify runners for the French Championships.
The route runs through the city streets and along the banks of the Moselle, so it is a town race with river sections rather than a countryside loop. The semi-marathon dates back to 1996, giving it a longer history than many local road events in the region. It draws competitive runners chasing qualifying standards, club runners from Moselle and nearby border areas, handisport athletes, and people choosing the 10 km as the shorter option. The event leans into local wordplay with the slogan “C’est Thion tour !”, and official timing is handled by Chronocompétition.