Admittedly when I was in Paris, I went to more designer vintage boutiques than usual because, PARIS. There were a few cheap and cheerful ones I checked out however they were extremely messy and much harder to rummage through (not even I could deal with the situation in some of these stores).
So these are the ones I actually enjoyed the shopping experience in:
Kiliwatch
Clara’s Vintage
Kilo Shop
Palace Callas
Vintage Clothing Paris
Nice Piece Vintage