I just watched the classic French film Les Dames du Bois de Bolougne (1945), with a screenplay by Robert Bresson and Jean Cocteau, from a story by Diderot.
What puzzles me is that the lovers (or ex-lovers) Jean and Hélène keep addressing each other by the formal vous and not the familiar tu. Am I missing some subtlety of the French language here, or does it have something to do with the psychology of l’amour?
While the pronoun ‘vous’ is considered to be formal, it is also considered to be more poetic. If you read classic French poetry or literature (try Cyrano de Bergerac for prime examples), you will find a lot of this. It’s sort of the ‘high style’ of French romantic speech.
So in answer to your question, a little of column A, a little of column B. The only reason I know this is from dating a Francophone with a fixation on the aforementioned play. 
I read Jane Eyre in French (or bits of it) and was also surprised that the hero and heroine called each other ‘vous’, right until after they were married. I’ve seen it in other C19th French novels, as well. As well as being a poetic, ‘high style’ kind of thing as Daerlyn mentions I get the impression that it was more common in the 19th century to be polite to your loved ones, because saying ‘tu’ had more of a connotation of speaking to servants or children. It’s a little like in Jane Austen when Emma calls her husband ‘Mr Knightly’ rather than ‘George’.
Cheese-eating surrender monkey here!
The rule about “tu” and “vous” is that if in doubt, you use “vous”. Speech has become less formal, but it’s not infrequent for older couples (grandparent age) to call each other vous, and in some families the children call their parents “vous” also. But between relatives, lovers, or any people in a close relationship this is now either an archaic use of the language or an affectation. It sounds rather snobbish when used by younger people.
But in 1945 it was pretty standard.
I call everybody “vous”.
It’s just easier that way.
I thought this was going to be a thread about the lyrics to “Lady Marmalade”.
Vous was used in most situation in the “old days” and like somebody said before it is more poetic.
In many classic novels, the kids would use Vous with their parents, etc…
It would not be done nowadays.
Wow, I didn’t know there were so many francophone dopers.
Salut tout-le monde!
-trupa, originalement de Dollard-Des-Ormeaux, Montreal.
I am from France, I try to lay low lately 
Actually, it was fun as a student of French to watch the tu-ing and vous-ing in the play. Now it’s been a while, but I believe Roxanne always used the tu, wheras our hero used the vous.
And what’s even more fun is trying to read History of the Empire of the Moon. Hurrah for non-standard spelling! I really do wish sometimes that it was my native language.
AL