The disclosure relates to a fixing device for fixing a first part and a second part together. The fixing device may include a nut non-rigidly coupled to the first part. The first part may have a fixing flange with at least one orifice positioned to accept a threaded shank coupled to the second part. A retainer may be proximate an inner diameter of the at least one orifice positioned to retain the nut within the fixing flange before the nut is screwed onto the threaded shank. The nut may have an externally threaded portion which may couple to the internally threaded portion of the orifice in the flange or of an element attached to the flange and to pass completely through the internally threaded portion until it is housed in a cavity for axially retaining the nut. Therefore, the nut may rotate freely before it is fastened to the threaded shank. The disclosure also relates to a turbomachine that utilizes this device and to an associated fixing method.