I wish I had read this forum before my purchase! I bought a pair Chypre natural in December to match my Birkin in 37.5 and never wore them then bought a black pair two weeks ago when it was quite busy on the weekend. I was wearing wide leg jeans and didn’t want to take too much time when trying them, I thought they felt fine…(I was going base off of a pair of extra I got while i was still a just in the early stages of pregnancy which fit at the time with a bit of room) . I wore the black Chypre twice now and the second time is when I noticed I should of got 38.. they my heel is on the back edge and it gave me a blister if I move forward my toe sticks out a smidge a bit. I’m so disappointed in myself lol my extras now don’t fit well either, thanks to the unfortunate pregnancy foot growth… I now have two pair of shoes I can’t exchange. I’ll have to suck it up. I def recommend people to size up.