Abstract: A fastener device for fastening a hollow part is made up of two mutually facing walls to at least one structural part. The device comprises a one-piece body of metal material presenting two main faces extending longitudinally between first and second ends of the body. Each main face includes a bearing portion in the vicinity of the first end of the body. The bearing portion is for being pressed against an inside surface of a respective one of the two walls of the hollow part, with each bearing portion including a fastener orifice for receiving a fastener member. The bearing portions are separated from each other by a slot extending from the first end of the body and over a determined depth within the body.