Sizing problem for Gillie skirt and Chloe shirt

Hi all, I recently discovered Sezane and would like to buy their Gillie skirt and Chloe shirt but am confused about the sizing.

I'm 159 cm tall and my overall measurement is 39"-28.5"-39.5"---hourglass shape with thicker thigh and wider shoulder. I generally take M/US8 for Tommy Hilfiger and Banana Republic tops and 29" in denim (Gap). Should I take EU40 for both Gillie skirt and Chloe shirt? or should I size down?