This is one of the provisions of 1996 legislation on the Cuban embargo
called The Helms-Burton Act
It did not go into effect immediately upon passage of the act, but requires the President of the United States to explicitly decide every six months whether to waive in or put it into effect.
In the event it is put into effect, it would allow anyone who had previously owned property nationalized by Cuba to sue any foreign company that made any use of these properties in business dealings with Cuba.
Given the fact that we have dealings with other countries such as Mexico who nationalized the property of American corporations at one time, and the fact that many of the original owners of this property have died in the interval, many questions are raised by this legislation. There are those who feel that politicians are leading on Cuban-Americans, encouraging them to believe that things will go back to the way they were under the Batista regime.