This movie is not just based on the book of the same title by former Greek Finance Minister Yanis Varoufakis. Varoufakis recorded almost every Eurogroup (Eurozone finance minister) meeting that he attended and he made these recordings available to Costa-Gavras, along with assorted notes and personal documents from his time as a minister, in order to be used as a basis for the movie.
Yanis Varoufakis chose the title ironically from a quote by Christine Lagarde after the Eurogroup meeting on Greek debt in June 2015: "For the moment we are short of a dialogue, the key emergency is to restore the dialogue with adults in the room."
Adults in the Room were also adapted for theatre. Stage production at Theater Neumarkt in Zurich had premiere on 27 September 2017.
Original literary source: "Adults in the Room. My Battle with Europe's Deep Establishment", book by Yanis Varoufakis, Bodley Head, London, 4-5-2017, 560 pp., ISBN: 978-1847924452.
Almost 6 minutes into the film, an old man, wearing a hat is seen in a cafe, saying "the communists!".
This is Vasilis Vasilikos, a Greek author, who wrote, among others, the novel "Z", upon which the multiply awarded film of the same name was based, also directed by Costa-Gavras.
Vasilikos is currently (February 2021) a member of the Greek Parliament with SYRIZA, the party whose leader and ex-Prime Minister is Alexis Tsipras, who is portrayed in this film.