Do I dress like an American?

Today I had an interesting experience.

You see, usually, until I open my mouth at least, people don't assume
I am American. They know I am not french (I am far too blonde and
pale and tall to be French), but they don't know where I am from, and
they don't assume the good ol' USA.

I don't dress like what they think of as typically American, ie:
Baggy jeans
Sweatshirts
T-shirts (big, baggy ones with writing on them)
white socks
tennis shoes (does not include the Paris-cool Converse All-Stars or
the "Retro Sneaks"--these are acceptable)
baseball caps
fanny packs
camera around the neck
shorts
khaki pants

No, I wear things that are a little teeny bit more French, like
jackets, fitted jeans, scarves, and dressier shoes. I always have--
this was normal for me in North Dakota and Wisconsin, too.

So today, when I looked outside and saw it was cool, I decided to top
my trouser-jeans (cut like trousers, made of denim) with a white
collared button-down shirt, red wool sweater, and navy courderoy
blazer. With dark socks and brown shoes, I figured I looked OK. I
even left the scarf behind, thinking I didn't really need it.

And, as we went to board the 14 metro line to head back to the girls'
apartment from the 4th arrondissement to the 13th, a man approached
us and immediately spoke to me in English.

I have no idea why.

Dr. B thinks maybe I looked British. What does that mean?

I am quite confused.

Tomorrow, I am wearing a scarf.