Actor Ali Suliman, who plays Suleiman, had to speak in French for some pivotal scenes in the series. Suliman asked show producers if they could push the scenes later in the production schedule so he could make sure his French sounded authentic and fluent.
Layla tells Jack that she and embedded operations officer Lance Miller met at "the farm," which is the codename for Camp Peary. Camp Peary is a top-secret, 10,000-acre training facility for CIA officers. The site is controlled by the CIA but listed in the U.S. Navy's inventory of naval bases.
Fleury-Mérogis prison, seen in Suleiman's Episode 105 flashback, is located just outside Paris, France, is the largest prison in Europe, housing approximately 4,300 inmates. The facility is known, in part, for its imprisonment of jihadi radicals and for its perceived ability to fuel the radicalization of formerly non-radical inmates.
For the job interview scene, executive producers wanted to shave off the actor's beard but couldn't do it due to the complex logistics of series production, which required scenes from various episodes to be filmed within the same day or week. Most television shows film episodes in chronological order.
The man seen escorting Dr. Nadler is the same man seen previously carrying a crate whom Suleiman stopped to speak, now cleaned up & changed per his orders.