I have this ALL the time and it's utterly frustrating and yes slightly racist, not asking me where I am from but questioning my answer as apparently saying I am French (born and raised) isn't enough, is utterly annoying I remember having a conversation with a hairdresser along the lines of:
" Where are you from?"
" Oh, I am French"
" No, but originally."
" Well originally, I am French, I was born and raised in France, NOW if you ask me where my parents are from, my mum is French and my dad is from X..."
" Oh yeah, I mean no offense but I could tell you weren't from France, France, I mean..."
"...
"
It's not as bad as one of the waiter I once had where I told him I was French and he went on like:
" Well more African than French though"
" Uh, no, I am French, I was born there, I was raised there, my mum is French and I have never ever stepped in Africa can't see how I can be more African than I am French ?
"
" Meh, mixed race people always culturally belong more to their ethnic heritage than the country they are born in. I mean I love Africa so nothing against it but I wouldn't consider you French no. " (He wasn't even French, the fuck.)
It drives me nuts. It's people being shocked that I have got the French accent while not looking like their preconceived idea of a French woman. It's frustrating, it's annoying, and it's definitely racist. If someone tell me they are British I accept that, I know people wouldn't question where I am ORIGINALLY from if I was white and suited their preconceived idea of what a French lady looked like even if I didn't really have the French accent to back that up.