Well... the 'presumed' Duke of course. He is a essentially Spanish citizen born in Spain and is, beyond being the undisputed ainé des capétiens, the future 3rd Duque de Franco and Grande de España.
When Philippe de Bourbon, Duc d'Anjou (grandson of Louis XIV) became Don Felipe V de Borbón, Rey de España, he renounced all his French claims and titles. The title Duc d'Anjou reverted to the French Crown.
In 1712 King Felipe V was offered the possibility to renounce his Spanish titles and re-assert his French claims. He refused. So beside the Treaty of Utrecht, negotiated and co-signed by all of Europes major powers, Philippe de Bourbon not once but even twice renounced all claims on the throne of France for himself and all his successors. Since the title Duc d'Anjou is a French title, Don Luis Alfonso de Borbón y Martínez Bordiú has no rights on the titles Duc d'Anjou, Duc de Touraine, Duc de Bourbon, Duc de Bourgogne and Duc de Berry he uses for himself and his sons.
I respect him for his dazzling ancestry, for being the ainé des capétiens. I think he is a charismatic person and very likeable too. But he must not pretend what he is not. He can not ignore international treaties, official renouncations and solemn promises of allegiance and the course of centuries because it suits his case.