UK citizen getting a French carte de sejour

UK citizen getting a French carte de sejour

This is a bit of a left-field post, I know. I am filing it under Travel, which I guess is appropriate enough. I am British, my wife is (born-in-the-ex-Yugoslavia) Canadian, and we live in France. With Brexit looming large and expat status in doubt all over Europe, my beautiful wife thought it would be a good idea for me to go along to the prefecture in Nice and try to get myself a carte de sejour.