Assembly comprising: - a pince-nez moulded in one piece and comprising a substantially planar structure which has a first rim provided with a first lens and a second rim provided with a second lens , said structure having a plane (n) which passes through said first and second rims and said first and second lenses , said first and second rims each being extended by a linkage which connects them together, said linkage being arranged to be in contact with a holding element intended to be placed on the nose of a user, said linkage being curved and having a first and a second point of inflexion , said pince-nez having a first ready-to-wear position wherein the pince-nez is arranged to be placed on the nose of a user and wherein the linkage is in the idle position where the first and second points of inflexion are distant from each other and a second position wherein the linkage is in a tension position wherein the first and second points of inflexion are close to each other; - a holding element intended to be secured to the pince-nez, having a curved shape and comprising a first and a second point of inflexion ; - a case intended to contain the pince-nez, provided with the holding element, said case having a first rim and a second rim and a linkage element connecting said first and second rims to each other, said first and second rims being spaced apart from each other by a distance d corresponding to the length of the case and being arranged to hold said pince-nez in the second position, when said pince-nez is housed in said case , said assembly being characterised in that , when the pince-nez is housed in the case , the entire structure thereof is housed in the case except for the linkage and the holding element , which remain visible. - a pince-nez moulded in one piece and comprising a substantially planar structure which has a first rim provided with a first lens and a second rim provided with a second lens , said structure having a plane (n) which passes through said first and second rims and said first and second lenses , said first and second rims each being extended by a linkage which connects them together, said linkage being arranged to be in contact with a holding element intended to be placed on the nose of a user, said linkage being curved and having a first and a second point of inflexion , said pince-nez having a first ready-to-wear position wherein the pince-nez is arranged to be placed on the nose of a user and wherein the linkage is in the idle position where the first and second points of inflexion are distant from each other and a second position wherein the linkage is in a tension position wherein the first and second points of inflexion are close to each other; - a holding element intended to be secured to the pince-nez, having a curved shape and comprising a first and a second point of inflexion ; - a case intended to contain the pince-nez, provided with the holding element, said case having a first rim and a second rim and a linkage element connecting said first and second rims to each other, said first and second rims being spaced apart from each other by a distance d corresponding to the length of the case and being arranged to hold said pince-nez in the second position, when said pince-nez is housed in said case , <EOS>