All the dialogues between William Brand (Ambassador van Dongen) and Billy Howle (Herman Knippenberg) are in genuine and comprehensible Dutch, though their pronunciation and intonation make it evident they don't really master the language.
When she speaks English, Monique's Québécois accent is really bad, but her French dialogue is straight-up atrocious for the entire duration of the series, which is explained by the fact that Jenna Coleman cannot speak French at all. This makes the original version of the series quite a painful watch for French speakers, as most of the time, they can't understand what she says in French if it's not subtitled. It's quite conspicuous as everyone else speaks perfect French (Alain/Charles, Nadine, Rémi, Juliette, etc.).
In the French dubbing, she's perfectly understandable, but there is no trace of a Québécois accent.
In several cutaway scenes involving airplanes, twin jet aircraft were featured flying long range flights. In the time period of the series, all long range flights were either using 4 engined jets like the Boeing 747, Douglas DC-8 and Boeing 707, or trijets like the McDonnell Douglas DC-10.
Twin jet flights of long distance did not start until the mid 1980s.
Twin jet flights of long distance did not start until the mid 1980s.