French referendum was the exact opposite of Brexit referendum.
The question asked was « Do we accept this constitution ? »
As you can imagine, barely anyone read it, so on the end most of voters choosed their response on this question : « Do I like my actual government ? »
But my point is, for the Brexit the question was simple, and could have been summarized as « Leave or stay ? » which is very easy to have an opinion on (even if the consequences were not that clear and, as many have stated in other comments here, an elaborated exit treaty should have been thought before asking).
So one one side, a complex question (due to the complexity of the text), and on the other a simple one.
And in the end, most of voters voted emotionally.
Maybe not that different after all.