A combination of doing Nazi Germany in History and rewatching why we fight made me wonder if there are any fics with a nazi spike and jewish buffy or something along those lines
or a spy fic or something like that
I've never come across any so any fics like this, so I don't mind whether it's a one shot or epic - both would be muchly appreciated

Hmm, that's a toughie.
I can't say that this is exactlyl what you're looking for but it has the right themes.

We Will Remember Them... by Lilachigh
Rated: U
Summary: In 1943 Spike is captured by the British army and given a chance to save Dru's life - and his own. And in 2001, Buffy is given a chance by Quentin Travers to travel back in time to save the world - again!
Complete

I just finished reading it myself and as a History major it really caught my interest. You've got the French Resistence and France occupied by the Nazi's here. The first chapters pretty much explain the why and the how. There is also reference, if I'm not mistaken, to Why We Fight so hopefully you'll like it.

- Arina Summer

spikeluver DOTCOM /SpuffyRealm/viewstory.php?sid=32088

Sorry, forgot to post the link above.

This might fit the bill somewhat.

http://www.cryptoffic.com/author/f-j/ggnoel/ggnoel_monster1.html

It's an older fic, but it has some of the items you're looking for.

thankyous
I love We will remember them - one of my faves I think
and I'm off to check out the older one now
xx

You will have to register at Elysian Field to read this. I think it would be worth it.

The Heart's Filthy Lesson: by MustangSally_RivkaT

http://dark-solace.org/elysian/viewstory.php?sid=663

In 2001 the evil from 1936 has reared its ugly head. A Nazi demon with an unpronounceable name and a vampire henchman has decided to use Sunnydale as a recruiting center for the disenfranchised and discontented undead. How will Buffy/Spike and the rest of the Scoobies manage to consign this particular evil back where it belongs?