The local opposition party M'YEU, lead by Patrice Bernard (who is the island's only butcher), has criticized the decision because the extension would be situated in a natural area where for everyone else extensions can only cover max. 30m2.
According to Mayor Bruno Noury the exception was imposed "from higher up" and is exceptionally allowed (by law) specifically because it is meant for sovereign security staff.
The royal family has said that all rules were abided by. The royal palace released a statement in which they said: "The permit was granted in a natural area on the basis of a derogation which authorizes the construction of collective equipment of general interest on the grounds of safety. The regulations in force and the advertising deadline have been respected." [source Radio Television Luxembourg)
Mr. Bernard has said that he will not start an official procedure against the building permit, but the opposition councilor spoke against the mayor's decision during a municipal council simply to make a point. Islanders have been refused a building permit in [that location] because it is a nature zone.
The location is unfortunate. The rugged, natural beauty of Ile d'Yeu makes it one of the most beautiful islands in France and, just like the rest of the Vendée, one of its best kept secrets. We get why the Belgian royal family loves our Vendéen island so much.
We do too!