A rotary piston machine, especially a rotary engine, that is suitable for use, in particular, as a Range Extender for an electrically operated motor vehicle, comprising a housing, a piston chamber that is defined in the housing by a first sidewall, a second sidewall and a peripheral wall interconnecting these sidewalls, a rotary piston that is rotatably arranged in the piston chamber and has a first face side and a second face side, wherein the first face of the rotary piston faces an inner side of the first sidewall of the piston chamber and the second face of the rotary piston faces an inner side of the second sidewall of the piston chamber, and wherein at least two working zones are formed between a peripheral surface of the rotary piston and the peripheral wall of the piston chamber, and at least one first lateral seal (36, 37) on the first and the second face sides (29, 30) of the rotary piston in order to seal intermediate spaces between the first and the second sidewall (14, 16), respectively, of the piston chamber and the first and the second face sides (29, 30), respectively, of the rotary piston relative to the working zones, wherein at least one ventilation bore is provided in the first and/or the second sidewall (14, 16) of the piston chamber, the ventilation bore being connected to at least one ventilation channel in the housing, wherein rotary piston has a central bore, and wherein at least one second lateral seal (38, 39, 40, 41) is provided on the first and the second face sides (29, 30) of the rotary piston in order to seal the respective intermediate spaces between the first and the second sidewall (14, 16) of the piston chamber and wherein the first and the second face sides (29, 30) of the rotary piston are provided relative to the central bore, wherein the at least one second lateral seal (38, 39, 40, 41) is arranged radially within the at least one first lateral seal (36, 37) characterized in that the at least one ventilation bore is arranged at a location that radially lies within the at least one first lateral seal (36, 37) and radially outside the at least one second lateral seal (38, 39, 40, 41). a housing, a piston chamber that is defined in the housing by a first sidewall, a second sidewall and a peripheral wall interconnecting these sidewalls, a rotary piston that is rotatably arranged in the piston chamber and has a first face side and a second face side, wherein the first face of the rotary piston faces an inner side of the first sidewall of the piston chamber and the second face of the rotary piston faces an inner side of the second sidewall of the piston chamber, and wherein at least two working zones are formed between a peripheral surface of the rotary piston and the peripheral wall of the piston chamber, and at least one first lateral seal (36, 37) on the first and the second face sides (29, 30) of the rotary piston in order to seal intermediate spaces between the first and the second sidewall (14, 16), respectively, of the piston chamber and the first and the second face sides (29, 30), respectively, of the rotary piston relative to the working zones, wherein at least one ventilation bore is provided in the first and/or the second sidewall (14, 16) of the piston chamber, the ventilation bore being connected to at least one ventilation channel in the housing, wherein rotary piston has a central bore, and wherein at least one second lateral seal (38, 39, 40, 41) is provided on the first and the second face sides (29, 30) of the rotary piston in order to seal the respective intermediate spaces between the first and the second sidewall (14, 16) of the piston chamber and wherein the first and the second face sides (29, 30) of the rotary piston are provided relative to the central bore, wherein the at least one second lateral seal (38, 39, 40, 41) is arranged radially within the at least one first lateral seal (36, 37) characterized in that the at least one ventilation bore is arranged at a location that radially lies within the at least one first lateral seal (36, 37) and radially outside the at least one second lateral seal (38, 39, 40, 41).