Thierry Tilly, 48, told the judge who sentenced him in Bordeaux that he would appeal to European courts, The Daily Telegraph of London reported. He said the French courts have no jurisdiction because he is a British national.
"You have convicted the French citizen but not the Englishman," he said.
The victims of Tilly's swindle included Guillemette de Vedrines, who died in 2010, her three children and five adult grandchildren. He got to know the family in 1999 when he worked for a secretarial school in Paris owned by Ghislaine de Vedrines, one of the matriarch's daughters.
Investigators said Tilly convinced the family they were under attack by Freemasons and other conspirators, getting them to hole up in their French chateau. When French authorities became suspicious, he moved the family to rented houses in Oxford, England.
Over the years, Tilly convinced the de Vedrines to hand over 3.6 million pounds ($5.7 million).
During the trial, Tilly claimed to be a member of the imperial Hapsburg family.
His own lawyer has said he is "20,000 leagues under the real world."
If Tilly does get to England, he could be in more trouble. His Oxford landlord says he owes 250,000 pounds ($396,000) in unpaid rent and damages.