They're leaving the cinema with Tintin and Haddock in Red Sea Sharks (page 1, frame 3)
They're certainly very similar, with the woman having the same sort of distinctive face and nose, though she seems to have lost the spectacles she had on in The Calculus Affair
. (Maybe her eyesight's improved, or maybe the ones she's wearing in The Calculus Affair
were fake, as part of her disguise, if we're going with the spy theory!)
A similar couple can just be seen behind Tintin and Haddock in panel 8 of page 11 of Red Sea Sharks
, though she's got a different haircut and he looks a little slimmer.
And I wonder if it's them in Seven Crystal Balls
(page 1), the man talking with Tintin and the woman sitting opposite them.
The man's certainly similar, but the woman looks too different to me - different face, nose, hair, clothes.
In the last post of this
old thread, Cigars of the Beeper speculates that the man in the theatre in Seven Crystal Balls
whom Yamillah divines is called Augustus may also be the same man as the man on the train and the man on the bus/plane from The Calculus Affair
. If it is him, he seems to have left his wife behind. (Maybe she only enjoys opera, and not music hall!) But as Cigars says, he may just be a recurring generic character, rather then meant to be literally the same man each time.
I bet they're based on some real-life persons that Hergé knew.
I wonder if the man might be another iteration of Hergé's dad or uncle?
It's nice to think they were based on actual people, and that they're meant to be the same people in each book. But even if Hergé wasn't being that specific or repeating them that consciously, I agree that they seem to represent the sort of respectable, petit-bourgeois people who'd have been part of Hergé's family upbringing - everything that Tintin isn't, and everything that Hergé seems to have spent a lifetime escaping from!
Maybe all these stultifyingly respectable background characters - such this couple and so many others - are more important to the "feel" of Tintin books than is often written about, in that they provide the contrast to Tintin's family-free life of adventure.
I'll need to go and look up the examples you've spotted in Tibet and Flight 714 now.