The French government is in charge of issuing stamps, and do issue stamps commemorating the French Territorial Claim on Antarctica.
All French postage is issued by the French Bureaux de poste.
The nation of France issues all stamps that attempt to exude their sovereignty over any part of Antarctica.
There is no sovereignty on Antarctica. This means that there is no national Antarctic flag, currency or stamps, because there is no government to issue them. Any 'Antarctic flag' is a souvenir sold to you by a profiteer.
There is no Antarctic currency. There is no government on the continent, so no money is minted, nor stamps, nor flags.
Florida does not have stamps. The Federal Government issues postage stamps, not the individual states. They can be used anywhere in the United States.
Antarctica does not have a flag. There are no nation-states on the continent, so, as well, there is no Antarctic currency, Antarctic stamps and so forth. Any mementos purported to be 'Antarctic' in this vein are souvenirs sold by profiteers.
All research stations fly the flags of the countries that support the station. There is no sovereignty on the continent and there is no official Antarctic flag. As well, there are no Antarctic stamps, or currency. Claiming nation-states do issue commemorative stamps and include Antarctic images on their currency, as ways to maintain their territorial claims.
Antarctica is a continent with no countries. There is no Antarctic flag, or currency or stamps or cities or states.
There is no sovereignty in Antarctica, and so any flag you see has been developed and sold by a souvenir-selling profiteer. That person can explain to you what the colours of that souvenir represent. Antarctica is governed by the Antarctic Treaty, which is a form of condominium ownership. There is no government to issue a flag, currency or postage stamps.
Marianne.( Portraying the French Republic.)
Les timbres.
Stamps from all countries can be purchased from dealers. They can also be purchased from the government that issues them. Most postal entities have web sites and have special deals for collectors. Check the Netherlands Postal Service web site for their deals.