The purpose was to develop the interior separately from the coastal area around Cayenne. The labor force consisted of 500 Annamite prisoners who had revolted against French rule in Indochina, and were brought in 1931. The plan did not work out, owing to the difficulties of railroad construction in the interior, although the ruins of the three prisons may still be seen.
During this period, the postage stamps of French Guiana were overprinted with several variations on "TERRITOIRE DE L'ININI", and the omnibus issues for the Colonial Arts Exhibition in 1937 and the New York World's Fair in 1939 included stamps inscribed "ININI". Despite the limited audience, the stamps of Inini are commonly available at minimal prices today.