The march by residents of Mataiea was held despite a statement by the government of Edouard Fritch in February that its deal with the Americans had become void.
The demonstrators, who included local fishermen and families, are opposed to building the islands in the Atimaono lagoon, saying the area is their food source.
The government said its agreement with the Seasteading Institute was not a legal document and that it expired at the end of 2017.
It also said it hoped that this would end the debate about the floating islands.
