A joining element for a chain, in the shape of a brise ring shaped to match the shape and sizes of a link of said chain wherein said joining element: comprises two overlapping oval half-rings (10a, 10b) made of rigid metal placed side-by-side which are joined to each other by a connecting portion and are each formed by two semicircular portions joined to each other at an end by a linear middle portion, comprises a connecting portion which joins the free ends of the two opposite semicircular portions (108, 112) of the two oval half-rings (10a, 10b), wherein a first semicircular portion is connected to a first linear middle portion, said first linear middle portion is connected at the other end to a second semicircular portion which in turn is connected to a connecting portion, wherein said connecting portion is connected at the other end to a third semicircular portion which is spaced apart from and faces the first semicircular portion, said third semicircular portion is connected to a second linear middle portion facing the first linear middle portion, said second linear middle portion is connected to a fourth semicircular portion which is spaced apart from, and faces the second semicircular portion, characterized in that - the connecting portion is linear and is directly interposed between the second semicircular portion and the third semicircular portion, and is parallel to and spaced apart from the linear middle portions (106, 114), or - the connecting portion has a curved S-shaped outline and is directly interposed between the second semicircular portion and the third semicircular portion, or - the connecting portion has an oblique outline with respect to the middle linear portions (106, 114) and is interposed transversely between the second semicircular portion and the third semicircular portion. comprises two overlapping oval half-rings (10a, 10b) made of rigid metal placed side-by-side which are joined to each other by a connecting portion and are each formed by two semicircular portions joined to each other at an end by a linear middle portion, comprises a connecting portion which joins the free ends of the two opposite semicircular portions (108, 112) of the two oval half-rings (10a, 10b), wherein a first semicircular portion is connected to a first linear middle portion, said first linear middle portion is connected at the other end to a second semicircular portion which in turn is connected to a connecting portion, wherein said connecting portion is connected at the other end to a third semicircular portion which is spaced apart from and faces the first semicircular portion, said third semicircular portion is connected to a second linear middle portion facing the first linear middle portion, said second linear middle portion is connected to a fourth semicircular portion which is spaced apart from, and faces the second semicircular portion, characterized in that - the connecting portion is linear and is directly interposed between the second semicircular portion and the third semicircular portion, and is parallel to and spaced apart from the linear middle portions (106, 114), or - the connecting portion has a curved S-shaped outline and is directly interposed between the second semicircular portion and the third semicircular portion, or - the connecting portion has an oblique outline with respect to the middle linear portions (106, 114) and is interposed transversely between the second semicircular portion and the third semicircular portion.