D'orsay pumps
They are based on a shoe popularised by the Comte D'Orsay
a 19th century French dandy. The fashion then was for what were known as slippers, similar to our modern ballet pumps. He had cutaway sides made in his slippers in order to make his legs appear longer. A D'Orsay shoe nowadays just means any shoe with cutaway sides, but usually these days with a high heel.
an example:
