A motor vehicle key includes a casing, an insert, a mechanism for deploying the insert, an upper rim of an upper area of the support, and a lower rim of a lower area of the support, the upper rim and the lower rim extending between a rotation end of the key and a blocking end, the upper area and the lower area forming a movement sector of the support, a first play between the rotation end and the support. The movement sector of the support includes at least one constriction point, exhibiting a second play, smaller than the first play, in relation to said support.