In my limited and stunningly unsuccessful experience, I've found that women like presents that have had some thought put into them, and are kinda kooky.
In your situation, I'd make a "paris survival kit", packaged in a little xmas box.
Include a small guidebook and a beret. Include some sweets for sucking on the plane. Just a few really small things. It's just something to show you've put some effort into her.
It sounds totally lame, but it works well if you put some thought into it.
It also means if she hasn't bought u a crimbo present u can avoid the embarrassment by saying its not really a christmas present, but a holiday gift.
This could be why I'm single though
oh my god that's the sweetest thing ever, well done Tallaght01!
She'll love that!! Do it dooooo it!