Sid Meier's Civilization V

Sid Meier's Civilization V

R.E.D. WWII Edition
France is jumping the gun
I'm playing as Germany (Because why not) and I've invaded Poland. But the very next turn, France declares war on me. Normally it would be about two turns before Britain and France declare war but Britain stays completely neutral, it's only France that attacks. Is this supposed to happen? Normally Britain and France delcare war on the same turn. And if it wasn't, I'd at least espect Britain to do it first.