In June 1798, at the time of the capture of
Malta by
Napoleon Bonaparte en route to his expedition of
Egypt, part of the
Mediterranean campaign of 1798, Doublet formed part of the delegation which negotiated the terms for the surrender of the Order on board Orient, Napoleon's flagship. He intervened when negotiating the amount of the allowance allocated to the Grand Master. Pointing out that the proposed amount appeared insufficient to him, Napoleon's only retort was to address the problem directly to the Republic. As he had with the other Frenchmen in the Order that he thought to be of some use to him, the General proposed Doublet accompany him to Egypt. Because of Doublet's age—he was almost 50 years old—and his family for which he was the only support, Doublet declined the proposal courteously but firmly. His refusal angered Napoleon, who did not appreciate anyone denying his will, but the future emperor confided to
Junot, his aide-de-camp, that this man had good qualities because he had substance. During the occupation of Malta by
France (June 1798/September 1800), his competencies were again put to use by the French authorities because of his knowledge of the land and because he was French and thus reliable in the eyes of the occupiers. He is named as of June 1798 Secretary General to the Commission of Government installed by Napoleon at the time of his stay. On 10 November 1799 he became
Commissioner to replace
Regnaud de Saint Jean d'Angély who is recalled to France, a position that he remained until the surrender of Valletta on 5 September 1800. The President of this commission was another Frenchman, Citizen
Jean de Bosredon de Ransijat, formerly commander of the Order and also its former treasurer.
Business of the Grand Master Following the capture of Malta by the troops of Bonaparte and in the débacle of the Order which followed, Doublet was shown to have communicated to the French authorities the secret code that the Grand Masters Hompesch and, before him, Rohan used to safeguard their diplomatic mails. Indeed, as a sovereign order, the Order of Malta then exchanged an abundance of correspondence with the different
states around Europe. Bonaparte intercepted several messages to the Order's
Grand Master, and its honorary Grand Master, the Czar of Russia. Bonaparte requested the decipher code.
Ferdinand von Hompesch zu Bolheim yielded to this requirement and instructed Doublet to hand over of this secret code. These letters did not bring anything that the General-in-chief did not already know except perhaps, amusing details, certain appreciations of his own person emanating from French diplomats. However, Doublet had already aroused the jealousy of several members of the order, he was von Hompesch's right-hand man, and he was of French birth. A rumour quickly circulated that charged Doublet with the entire responsibility of having delivered the cipher to the enemy. Some of his accusers even asserted that Doublet was a traitor, a secret agent on the payroll of Napoleon who had been introduced within the Order to undermine it. In a similar case, the
Proclamation of St Petersburg, signed by former members of the Order in an effort to please the Czar, posited that Hompesch was incompetent and defeatist. This is also the case in a published booklet partisan with
St Petersburg by an old bodyguard of the
Count of Artois (the future
Charles X). One can seriously doubt the objectivity of these writings insofar as their authors were obligated to the Czar, placed under his authority they tried to restart in a ridiculous and pitiful way the previous glories of a broken and deposed order. Indeed, Czar Paul I had been designated "" of the Order and, after its dissolution in Malta, he tried to reconstitute it within the framework of the recently established Priory of Russia. It was thus important to discredit von Hompesch and, if unhappy with the Grand Master but still taking into account his rank, could not openly be shown to be a traitor, at the very least by deferring the crime on his closest collaborators one could make him a traitor by incompetence, weakness and breach. Besides, Tzar Paul I managed to achieve his goal since after the , he is proclaimed Grand Master by some of the members of the Order in exile whom he had hastened to accommodate following their expulsion from Malta (the Grand Master was not recognised by the
Pope because Tzar Paul I was married and of
Russian Orthodox religion). Doublet, the
ex donat, shared these calumnies with Bosredon de Ransijat, another renegade in the eyes of Order. Doublet's honour was wounded by this cabal, but more especially as he always hoped for the re-establishment of the Order and his return to Malta, Doublet protested his innocence in this business until the end of his days, innocence which will be attested to by several direct witnesses, including Matthius Poussielgue, Napoleon's finance adviser at the time of these events. == Exile (1800–1824) ==