Clamping collar

A clamping system for connecting two tubes whose facing ends have clamping surfaces protruding relative to a cylindrical external surface of said tubes, the system comprising a collar having a strip configured to cooperate with said clamping surfaces, the collar being configured to be tightened by a reduction in a diameter of the strip, the strip having a first flank and a second flank between which an inner recess configured to receive the clamping surfaces is delimited, the clamping system comprising at least one retaining clip comprising a cross-member which extends across the inner recess, a first wing and a second wing which extend radially outwardly relative to the cross-member by covering respectively the first flank and the second flank, and a first retaining configuration and a second retaining configuration each comprising at least one retaining lug which extends radially inwardly relative to the cross-member, the cross-member being able to be removed upon tightening of the collar.