In cases where a lessee of buildings used as residences dies with no heir, and persons with a relationship to the building lessee similar to a de facto marital relationship or a foster parent and child relationship, although notice of marriage or adoption has not been submitted, live together with the building lessee, said persons shall succeed to the rights and duties of the building lessee. However, that this shall not apply when said persons express intentions contrary to those of the building lessor within one month of being made aware that the building lessee died without heirs.