Abstract: The invention relates to a device for fixing an accessory such as a positioning sensor to a bodywork part of a motor vehicle, said accessory being found on the side of the bodywork part that faces towards the inside of the vehicle and in register with an orifice made through said bodywork part. It comprises a jacket suitable for containing the accessory, and a support suitable for being secured to the bodywork part on the side of said bodywork part that faces towards the inside of the vehicle, the jacket containing the accessory being suitable for being received inside the support by being inserted from the outside of the vehicle through the orifice formed in the bodywork part, said jacket containing the accessory also being suitable for being withdrawn from the support from the outside of the vehicle by being extracted through the orifice formed in the bodywork part.