A device includes a clamping collar having a belt that has two substantially cylindrical faces and that is suitable for being tightened around an article to be clamped; and at least one positioning including a securing plate that is disposed facing a first face of the belt while being retained relative to the belt; and a positioning portion that is suitable for positioning the device relative to the article to be clamped. When the collar is in its initial, non-tightened state, the securing plate is braced against the first face of the belt, wherein at the beginning of tightening, the plate deforming causes the bracing effect to cease, thereby allowing the belt and the plate to move relative to each other. The plate is suitable for being deformed while the collar is being tightened onto the article so as to present curvature that matches the curvature of the belt.