France supports Argentina in the rightful seizure of their own land.
The land has been in control by Britain since 1841, and the modern Argentinian government has had no claims on the island.
It is like saying that Spain still has control over the Phillipines. Or that Britain still owns the east coast of the United States. Or that France still owns part of Canada.
Both Argentina and Britain are told to not escalate the current situation, but to find peace and a middleground.