To all ditassima owners... how small do they actually run?

I've found a pair finally but the owner says they run very small.
What size do you wear normally and what size in the ditassima?
Thank you
Hi maybe to late but hope this helps , I agree they ran small, for me 1 size but I noticed the T bar that can cause the ankle straps to become short and limit the amount of holes available if you have very high in steps.

I wear a 37 on average yet needed a 38 but I have weird shaped feet , good luck Sharon
 
My Ditassima's are the same size as my Pigalle Follies and So Kate, and fit perfectly. I wear a 8.5 US and a 39 is perfect. You could size up as the strap helps keep your foot in, but I wouldn't size down.