In 1946, after more than three centuries of colonization, French islands Guadeloupe and Reunion become French departments. Even if these two islands have similarities (tropical latitudes, volcanism and populations descending from the slave trade and forced labor), their inhabitants’ cultures of inhabiting and relationship to France are different. This paper offers to initiate a comparative analysis of patrimonial processes and recognitions of public buildings and urban houses built in the 20th century in Guadeloupe and Reunion, based on the study of files for historical monument classification requests, regional Inventories and other patrimonial studies conserved in the administrative archives of the two islands’ Direction des Affaires Culturelles. This paper is interested in looking into representations and arguments used by the State Services. What architectures are looked at? In which ways are they understood and appreciated? Based on what criteria and arguments in the Caribbean Island and in the one in the Indian Ocean? The various heritage missions and surveys on architecture launched since 1949 struggle, in fact, to recognize the specificities of these creolized cultures and have long been the vectors of national administrative and heritage culture. A more inclusive approach based on the notion of creolization would make it possible to reshape the heritage perspective.