hidden references / inside jokes

being a belgian, i could notice a few hidden cultural references:

-> isabelle one moment sings 'beats of love' from the belgian band 'nacht und nebel', which was a hit in europe in the 80's. also, 'nacht und nebel' is a german expression meaning 'secret' or 'secretely' or something like that. but i don't know if that was intended.

-> when isabelle is with her girlfriend, she says 'à tantôt' to xavier (see you later), a phrase only belgians use and maybe the french speaking swiss also. the french would say 'à tout de suite' or 'à toute à l'heure'.
(for the interested: in belgium we would use 'à tout à l'heure' if we'll meet again in an hour or so and 'à tantôt' if we'll meet again in several hours)

it's funny to realise you're kind of privileged to notice these things. did anyone else notice some other references?