I have the Lio ones, not sure if they're sizing would be the same, but I am usually a 35.5-36, but my Repettos are a 36.5 and they are perfect. They never cut into my feet at all (mine are just the leather ones, not patent)
As Zarina says, I also only wear mine in summer or when my feet have been torn to shreds in a pair of new shoes so I wouldn't want them to be too snug.