An assembly including a support panel of an internal fixed structure, a thermal protection element and a plurality of fastening systems. Each fastening system includes a female part secured to the support panel and which has, in its interior, a circular shoulder, and a male part including a sleeve pierced with a main bore, a slide movable in translation in the main bore and a plurality of balls. For each ball, the sleeve has a secondary bore, and each ball is movable along the secondary bore between a locking position and an unlocking position. The slide is movable in translation between a blocking position and an unlocking position. Such an assembly makes it possible to fasten the thermal protection element to the support panel in a simple and rapid manner, also permitting easy removal if necessary.