In this excerpt from a letter of 5 July 1789, the Marshal de Broglie, head of the royal army who led a conservative faction at court, expresses his fears that amid the current unrest, the royal garrison and prison at the Bastille might come under attack. He advocates stationing reinforcements there to suppress an uprising.
To return to the matters in your letter, I will say straightaway that with regard to the Bastille, there are two areas of concern: the commandant himself and the type of garrison. To obviate these difficulties I have advised His Majesty to instruct the Count de Puységur to confer with Monsieur de Villedeuil [Minister for the King's Household and Paris] and recommend a good senior officer who can be entrusted with commanding the Bastille. You must dispatch 30 Swiss Guards, today if you can but certainly tomorrow to augment the garrison. . . . Make sure that they are under a very steady officer. As soon as the artillery regiment arrives, you must send in a small detachment of gunners to determine if the cannons are in good working order and to use them if it comes to that. This would be extremely unfortunate, but happily it is highly unlikely.
Source: Pierre Caron, "La tentative de Contre-Revolution de juinjuillet 1789," Révue d'histoire moderne, vol. 8 (1906), 26.