I can't believe it took me so long to notice how different French punctuation was. It wasn't until I started trying to write in French, and was corrected by French people, that I first realized.
Of course, everyone notices that French quotation marks are not like ours. The « and » are the most obvious difference from English books. They're called guillemets. I find French usage confusing at times, because there is often a guillemet to open a quotation, but not to close it again. When a single person is going on and on, the guillemet is reversed at the beginning of each new paragraph, as at the top of the photo, above. Next, each new person's speech is shown by a dash, but where does the speaking end? Sometimes the speaker stops talking in the middle of a paragraph, but there is nothing in the punctuation to show where the speech stops and the narrative begins. You just have to guess.*
What I hadn't noticed, though, was that the exclamation points, colons, semi-colons, and question marks are also different: they had a space in front of them. In other words, you don't write "Alors?" but "Alors ?" Not "Non!" but "Non !"
Also, check out this French computer keyboard. Can you find the period? (Full stop, to our British friends.) It's above the G. Yes, that's right. To put in a period on a French keyboard, you have to hit the shift key.
*Another example of the (lack of) precision of the French language! Although technically speaking, punctuation isn't language.