This research analyses the international relations among the Amazon countries regarding the sharing of the Amazon Trans-Frontier Basin, involving the Amazon Cooperation Treaty (ACT), in which there was the exclusion of French Guiana. This factor has sparked interest in further study of the Brazilian approach with the excluded country through the construction of the Oiapoque Bridge, which is completed since 2011 but has not been inaugurated yet. The reasons will be uncovered through the work.