French Polynesia has signed a memorandum of understanding with a US group to build a floating city in the territory.
The deal was signed by a minister Jean-Christophe Bouissou and the executive director of the Seasteading Institute in San Francisco, which is backed by Paypal founder and billionaire Peter Thiel.
The agreement clears the way for feasibility studies to create a legal structure for seazones with a special governing framework.
The Institute chose French Polynesia for its venture because it found that its links to France, its autonomy and relatively calm waters, offered a suitable environment to place a floating island.
Randolph Hencken said the venture was poised to launch a seasteading industry that would provide environmental resiliency to the millions of people threatened by rising sea levels.
The agreement was expected to be signed by French Polynesia's president Edouard Fritch but he stayed home because of a cabinet re-shuffle.
The institute's website says it wants to work with a team of marine biologists, nautical engineers, aquaculture farmers, attorneys, researchers and artists to enable seastead communities - or floating cities.