Le Monde has an interesting map of the referendum results département-by-département. I don’t know enough about French political geography to understand all the permutations, but there’s no surprise in seeing leftish areas like Nord-Pas de Calais voting strongly non.
More surprising, for a British observer, is that Brittany voted yes, given the ferocious anti-EU sentiment found in the west of England. Strongest Yes from central Paris, unsurprisingly.
Link (and discussion) at MetaFilter.