"I think Charles X wanted to be buried here, I think things should stay that way," Louis Alphonse de Bourbon told reporters at the Kostanjevica Franciscan monastery in Nova Gorica, near the Italian border.
Charles X died in exile in 1830 after a revolution put an end to his six-year reign.
He abdicated and was replaced by Louis-Philippe d'Orléans, who squeezed out Charles's grandson, Henri d'Artois, and reigned as "king of the French" until another revolution in 1848.
Since then the two houses have contested the succession, to no good end since the monarchy has not been restored in any form.
Campaign group furious
The organisers of a campaign to bring the remains to the Saint Denis basilica, north of Paris, slammed the declaration.
Citing a statement by Louis Alphonse that said that accepting the return of the remains would be to "accept the end of hopes of restoration", history teacher Julien Morvan claims that Louis Alphonse took a different position on a visit to Paris in 2002.
Morvan also challenges Louis Alphonse's right to decide on the issue, since he is not a direct descendant of the dead king.
The group say they are not royalists, just interested in the French monarchy, so the question of restoration is of little importance to them.